【解讀中考2016年中考數(shù)學(xué)復(fù)習(xí)專題04 分式及其運(yùn)算

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1、專題04 分式及其運(yùn)算 ?解讀考點(diǎn) 知　識(shí)　點(diǎn) 名師點(diǎn)晴 分式的概念 整式A除以整式B，可以表示成 的形式，如果除式B中含有字母，那么稱 為分式． 若B≠0，則 有意義；若B=0，則 無(wú)意義；若A=0且B≠0，則 ＝0. 分式的基本性質(zhì)及應(yīng)用 1.分式的基本性質(zhì) 要熟練掌握，特別是乘或除以的數(shù)不能為0 2.分式的變號(hào)法則 分式的分子、分母與分式本身的符號(hào)，改變其中任何兩個(gè)，分式的值不變. 3.分式的約分、通分 通分與約分的依據(jù)都是分式的基本性質(zhì) 4.最簡(jiǎn)分式 分子與分母沒(méi)有公因式 分式的運(yùn)算 1.分式的加減法 異分母的分式相加減，要先通分，然后再加

2、減 2.分式的乘除法、乘方 熟練應(yīng)用法則進(jìn)行計(jì)算 3.分式的混合運(yùn)算 應(yīng)先算乘方，再將除法化為乘法，進(jìn)行約分化簡(jiǎn)，最后進(jìn)行加減運(yùn)算．若有括號(hào)，先算括號(hào)里面的．靈活運(yùn)用運(yùn)算律，運(yùn)算結(jié)果必須是最簡(jiǎn)分式或整式． ?2年中考 【2015年題組】 1．（2015常州）要使分式有意義，則x的取值范圍是（　?。? A． B． C． D． 【答案】D． 【解析】 試題分析：要使分式有意義，須有，即，故選D． 考點(diǎn)：分式有意義的條件． 2．（2015濟(jì)南）化簡(jiǎn)的結(jié)果是（　　） A． B． C． D． 【答案】A． 考點(diǎn)

3、：分式的加減法． 3．（2015百色）化簡(jiǎn)的結(jié)果為（　　） A． B． C． D． 【答案】C． 【解析】 試題分析：原式====．故選C． 考點(diǎn)：分式的加減法． 4．（2015甘南州）在盒子里放有三張分別寫有整式a+1，a+2，2的卡片，從中隨機(jī)抽取兩張卡片，把兩張卡片上的整式分別作為分子和分母，則能組成分式的概率是（　?。? A． B． C． D． 【答案】B． 【解析】 試題分析：分母含有字母的式子是分式，整式a+1，a+2，2中，抽到a+1，a+2做分母時(shí)組成的都是分式，共有3×2=6種情況，其中a+1，a

4、+2為分母的情況有4種，所以能組成分式的概率==．故選B． 考點(diǎn)：1．概率公式；2．分式的定義；3．綜合題． 5．（2015龍巖）已知點(diǎn)P（a，b）是反比例函數(shù)圖象上異于點(diǎn)（﹣1，﹣1）的一個(gè)動(dòng)點(diǎn)，則=（　?。? A．2 B．1 C． D． 【答案】B． 考點(diǎn)：1．反比例函數(shù)圖象上點(diǎn)的坐標(biāo)特征；2．分式的化簡(jiǎn)求值；3．條件求值． 6．（2015山西?。┗?jiǎn)的結(jié)果是（　　） A． B． C． D． 【答案】A． 【解析】 試題分析：原式====，故選A． 考點(diǎn)：分式的加減法． 7．（2015泰安）化簡(jiǎn)：的結(jié)果等于（

5、　　） A． B． C． D． 【答案】B． 【解析】 試題分析：原式====．故選B． 考點(diǎn)：分式的混合運(yùn)算． 8．（2015萊蕪）甲乙兩人同時(shí)從A地出發(fā)到B地，如果甲的速度v保持不變，而乙先用v的速度到達(dá)中點(diǎn)，再用2v的速度到達(dá)B地，則下列結(jié)論中正確的是（　?。? A．甲乙同時(shí)到達(dá)B地 B．甲先到達(dá)B地 C．乙先到達(dá)B地 D．誰(shuí)先到達(dá)B地與速度v有關(guān) 【答案】B． 考點(diǎn)：1．列代數(shù)式（分式）；2．行程問(wèn)題． 9．（2015內(nèi)江）已知實(shí)數(shù)a，b滿足：，，則|= ． 【答案】1． 【解析】 試題分析：∵，，∴，，

6、∴，∵，，兩式相減可得，，，∴，即，∴==1．故答案為：1． 考點(diǎn)：1．因式分解的應(yīng)用；2．零指數(shù)冪；3．條件求值；4．綜合題；5．壓軸題． 10．（2015黃岡）計(jì)算的結(jié)果是________． 【答案】． 【解析】 試題分析：原式===．故答案為：． 考點(diǎn)：分式的混合運(yùn)算． 11．（2015安徽省）已知實(shí)數(shù)a、b、c滿足a＋b＝ab＝c，有下列結(jié)論：①若c≠0，則；②若a＝3，則b＋c＝9；③若a＝b＝c，則abc＝0；④若a、b、c中只有兩個(gè)數(shù)相等，則a＋b＋c＝8． 其中正確的是 （把所有正確結(jié)論的序號(hào)都選上）． 【答案】①③④． 考點(diǎn)：1．分

7、式的混合運(yùn)算；2．解一元一次方程． 12．（2015梅州）若，對(duì)任意自然數(shù)n都成立，則 　， ??；計(jì)算： ?。? 【答案】；；． 【解析】 試題分析：===，可得，即：，解得：a=，b=； m===，故答案為：；；． 考點(diǎn)：1．分式的加減法；2．綜合題． 13．（2015河北省）若，則的值為 ． 【答案】． 【解析】 試題分析：∵，∴原式==，故答案為：． 考點(diǎn)：分式的化簡(jiǎn)求值． 14．（2015綏化）若代數(shù)式的值等于0，則x=_________． 【答案】2． 【解析】 試題分析：由分式的值為零的條件得，2x﹣6≠0，由，得x=2或x=3，

8、由2x﹣6≠0，得x≠3，∴x=2，故答案為：2． 考點(diǎn)：分式的值為零的條件． 15．（2015崇左）化簡(jiǎn)：． 【答案】． 考點(diǎn)：分式的混合運(yùn)算． 16．（2015桂林）先化簡(jiǎn)，再求值：，其中． 【答案】，． 【解析】 試題分析：分解因式后，利用除法法則變形，約分得到最簡(jiǎn)結(jié)果，把x的值代入計(jì)算即可求出值． 試題解析：原式==，當(dāng)時(shí)，原式===． 考點(diǎn)：分式的化簡(jiǎn)求值． 17．（2015南京）計(jì)算：． 【答案】． 【解析】 試題分析：首先將括號(hào)里面通分運(yùn)算，進(jìn)而利用分式的性質(zhì)化簡(jiǎn)求出即可． 試題解析：原式== ==． 考點(diǎn)：分式的混合運(yùn)算． 18．（2015蘇

9、州）先化簡(jiǎn)，再求值：，其中． 【答案】，． 考點(diǎn)：分式的化簡(jiǎn)求值． 19．（2015鹽城）先化簡(jiǎn)，再求值：，其中a=4． 【答案】，4． 【解析】 試題分析：根據(jù)分式混合運(yùn)算的法則把原式進(jìn)行化簡(jiǎn)，再求出x的值代入進(jìn)行計(jì)算即可． 試題解析：原式===； 當(dāng)a=4時(shí)，原式==4． 考點(diǎn)：分式的化簡(jiǎn)求值． 20．（2015成都）化簡(jiǎn)：． 【答案】． 【解析】 試題分析：括號(hào)內(nèi)先通分，同時(shí)把除法轉(zhuǎn)化為乘法，再用分式乘法法則計(jì)算機(jī)即可． 試題解析：原式=． 考點(diǎn)：分式的加減法． 21．（2015資陽(yáng)）先化簡(jiǎn)，再求值：，其中x滿足． 【答案】，． 考點(diǎn)：1．

10、分式的混合運(yùn)算；2．分式的化簡(jiǎn)求值． 22．（2015達(dá)州）化簡(jiǎn)，并求值，其中a與2、3構(gòu)成△ABC的三邊，且a為整數(shù)． 【答案】，1． 【解析】 試題分析：原式第一項(xiàng)約分后，兩項(xiàng)通分并利用同分母分式的減法法則計(jì)算得到結(jié)果，把a(bǔ)的值代入計(jì)算即可求出值． 試題解析：原式== ===，∵a與2、3構(gòu)成△ABC的三邊，且a為整數(shù)，∴1＜a＜5，即a=2，3，4，當(dāng)a=2或a=3時(shí)，原式?jīng)]有意義，則a=4時(shí)，原式=1． 考點(diǎn)：1．分式的化簡(jiǎn)求值；2．三角形三邊關(guān)系． 23．（2015廣元）先化簡(jiǎn)：，然后解答下列問(wèn)題： （1）當(dāng)時(shí)，求原代數(shù)式的值； （2）原代數(shù)式的值能等于嗎？為什么

11、？ 【答案】（1）2；（2）不能． 考點(diǎn)：分式的化簡(jiǎn)求值． 24．（2015涼山州）先化簡(jiǎn)：，然后從的范圍內(nèi)選取一個(gè)合適的整數(shù)作為x的值代入求值． 【答案】；當(dāng)x=2時(shí)，原式=0，當(dāng)x=－2時(shí)，原式=8． 【解析】 試題分析：原式括號(hào)中兩項(xiàng)通分并利用同分母分式的減法法則計(jì)算，同時(shí)根據(jù)除法法則變形，約分得到最簡(jiǎn)結(jié)果，將x=0代入計(jì)算即可求出值． 試題解析：原式=== =，∵滿足的整數(shù)有±2，±1，0，而x=±1，0時(shí)，原式無(wú)意義，∴x=±2，當(dāng)x=2時(shí)，原式=，當(dāng)x=－2時(shí)，原式=． 考點(diǎn)：分式的化簡(jiǎn)求值． 25．（2015廣州）已知A=． （1）化簡(jiǎn)A； （2）當(dāng)x滿足

12、不等式組，且x為整數(shù)時(shí)，求A的值． 【答案】（1）；（2）1． 考點(diǎn)：1．分式的化簡(jiǎn)求值；2．一元一次不等式組的整數(shù)解． 26．（2015白銀）有三張卡片（形狀、大小、顏色、質(zhì)地都相等），正面分別下上整式，，3．將這三張卡片背面向上洗勻，從中任意抽取一張卡片，記卡片上的整式為A，再?gòu)氖Ｏ碌目ㄆ腥我獬槿∫粡?，記卡片上的整式為B，于是得到代數(shù)式． （1）請(qǐng)用畫樹狀圖或列表的方法，寫出代數(shù)式所有可能的結(jié)果； （2）求代數(shù)式恰好是分式的概率． 【答案】（1）答案見試題解析；（2）． 【解析】 試題分析：（1）畫出樹狀圖，由樹狀圖即可求得所有等可能的結(jié)果； （2）由（1）中的樹狀圖，

13、可求得抽取的兩張卡片結(jié)果能組成分式的情況，利用概率公式求解即可求得答案． 試題解析：（1）畫樹狀圖： （2）代數(shù)式所有可能的結(jié)果共有6種，其中代數(shù)式是分式的有4種，所以P （是分式）==． 考點(diǎn)：1．列表法與樹狀圖法；2．分式的定義． 【2014年題組】 1．（2014年無(wú)錫中考） 分式可變形為（ ） A. B. C. D. 【答案】D． 考點(diǎn)：分式的基本性質(zhì)． 2.（2014年杭州中考）若，則w=（ ） A. B. C. D. 【答案】D． 【解析】

14、 試題分析：∵， ∴w=．故選D． 考點(diǎn)：分式的化簡(jiǎn)． 3.（2014年溫州中考）要使分式有意義，則x的取值應(yīng)滿足（ ） A. B. C. D. 【答案】A． 【解析】 試題分析：根據(jù)分式分母不為0的條件，要使在實(shí)數(shù)范圍內(nèi)有意義，必須．故選A． 考點(diǎn)：分式有意義的條件． 4.（2014年牡丹江中考）若x：y=1：3，2y=3z，則的值是（　?。? A．﹣5 B． ﹣ C． D． 5 【答案】A． 【解析】 試題分析：∵x：y=1：3，∴設(shè)x=k，y=3k，∵2y=3z，∴z=2k，∴．故選A． 考點(diǎn)

15、：比例的性質(zhì)． 5.（2014年涼山中考）分式的值為零，則x的值為（ ） A. 3 B. ﹣3 C. ±3 D. 任意實(shí)數(shù) 【答案】A． 考點(diǎn)：分式的值為零的條件． 6.（2014年常德中考）計(jì)算：　 【答案】． 【解析】 試題分析：原式===. 考點(diǎn)：分式的加減法． 7.（2014年河池中考）計(jì)算： ． 【答案】1． 【解析】 試題分析：根據(jù)分式加減法運(yùn)算法則直接計(jì)算：． 考點(diǎn)：分式加減法． 8.（2014年鎮(zhèn)江中考）化簡(jiǎn)：． 【答案】． 考點(diǎn)：分式的混合運(yùn)算．

16、 9.（2014年蘇州中考）先化簡(jiǎn)，再求值：，其中． 【答案】． 【解析】 試題分析：先將括號(hào)里面的通分后，將除法轉(zhuǎn)換成乘法，約分化簡(jiǎn). 然后代x的值，進(jìn)行二次根式化簡(jiǎn)． 試題解析：原式=． 當(dāng)時(shí)，原式=． 考點(diǎn)：1.分式的化簡(jiǎn)求值；2. 二次根式化簡(jiǎn)． 10.（2014年撫順中考）先化簡(jiǎn)，再求值：（1-）÷，其中x=（+1）0+（）-1?tan60°． 【答案】2+2． 【解析】 試題分析：原式括號(hào)中兩項(xiàng)通分并利用同分母分式的減法法則計(jì)算，同時(shí)利用除法法則變形，約分得到最簡(jiǎn)結(jié)果，利用零指數(shù)冪、負(fù)指數(shù)冪法則以及特殊角的三角函數(shù)值求出x的值，代入計(jì)算即可求出值． 試題解析：

17、原式=，∵x=（+1）0+（）-1?tan60°=1+2，∴當(dāng)1+2時(shí)，原式=2+2． 考點(diǎn)：1.分式的化簡(jiǎn)求值；2.零指數(shù)冪；3.負(fù)整數(shù)指數(shù)冪；4.特殊角的三角函數(shù)值． ?考點(diǎn)歸納 歸納 1：分式的有關(guān)概念 基礎(chǔ)知識(shí)歸納： 分式有意義的條件是分母不為零；分式無(wú)意義的條件是分母等于零；分式值為零的條件是分子為零且分母不為零． 注意問(wèn)題歸納： 分式有意義的條件是分母不為0，無(wú)意義的條件是分母為0． 分式值為0要滿足兩個(gè)條件，分子為0，分母不為0． 【例1】使分式有意義，則x的取值范圍是（　　） x≠1 B．x=1 C．x≤1 D．x≥1 【答案】A． 【解析】根據(jù)題意得

18、：x-1≠0，解得：x≠1．故選A． 考點(diǎn)：分式的有關(guān)概念． 【例2】分式的值為零，則x的值為（ ） A. 3 B. ﹣3 C. ±3 D. 任意實(shí)數(shù) 【答案】A． 考點(diǎn)：分式的有關(guān)概念． 歸納2：分式的性質(zhì) 基礎(chǔ)知識(shí)歸納： 分式的分子與分母都乘以（或除以）同一個(gè)不等于零的整式，分式的值不變．用式子表示為 注意問(wèn)題歸納： 分式的基本性質(zhì)是分式變形的理論依據(jù)，所有分式變形都不得與此相違背，否則分式的值改變； 將分式化簡(jiǎn)，即約分，要先找出分子、分母的公因式，如果分子、分母是多項(xiàng)式，要先將它們分別分解因式，然后再約分，約分應(yīng)徹底

19、； 巧用分式的性質(zhì)，可以解決某些較復(fù)雜的計(jì)算題，可應(yīng)用逆向思維，把要求的算式和已知條件由兩頭向中間湊的方式來(lái)求代數(shù)式的值． 【例3】化簡(jiǎn)的結(jié)果是（ ） B． C． D． 【答案】D． 考點(diǎn)：分式的性質(zhì)． 【例4】已知x+y=xy，求代數(shù)式-（1-x）（1-y）的值． 【答案】0． 【解析】∵x+y=xy，∴-（1-x）（1-y）=-（1-x-y+xy）=-1+x+y-xy=1-1+0=0． 考點(diǎn)：分式的性質(zhì)． 歸納 3：分式的加減運(yùn)算 基礎(chǔ)知識(shí)歸納： 加減法法則：① 同分母的分式相加減：分母不變,分子相加減 ② 異分母的分式相加減：先通分,變

20、為同分母的分式,然后再加減 ． 注意問(wèn)題歸納： 1.分式加減運(yùn)算的運(yùn)算法則：同分母分式相加減，分母不變，分子相加減；異分母分式相加減，先通分，變?yōu)橥帜傅姆质剑缓笤偌訙p． 異分母分式通分的依據(jù)是分式的基本性質(zhì)，通分時(shí)應(yīng)確定幾個(gè)分式的最簡(jiǎn)公分母.求最簡(jiǎn)公分母的方法是：①將各個(gè)分母分解因式；②找各分母系數(shù)的最小公倍數(shù)；③找出各分母中不同的因式，相同因式中取次數(shù)最高的，滿足②③的因式之積即為各分式的最簡(jiǎn)公分母． 【例5】計(jì)算：的結(jié)果是 ． 【答案】． 【解析】． 考點(diǎn)：分式的加減法． 【例6】化簡(jiǎn)的結(jié)果是　 【答案】． 考點(diǎn)：分式的加減法．

21、 歸納 4：分式的乘除運(yùn)算 基礎(chǔ)知識(shí)歸納: 1.乘法法則：分式乘分式,用分子的積作為積的分子,分母的積作為積的分母.乘方法則：分式的乘方,把分子、分母分別乘方． 2.除法法則：分式除以分式,把除式的分子、分母顛倒位置后與被除式相乘． 注意問(wèn)題歸納：分式乘除法的運(yùn)算與因式分解密切相關(guān)，分式乘除法的本質(zhì)是化成乘法后，約去分式的分子分母中的公因式，因此往往要對(duì)分子或分母進(jìn)行因式分解（在分解因式時(shí)注意不要出現(xiàn)符號(hào)錯(cuò)誤），然后找出其中的公因式，并把公因式約去． 【例7】計(jì)算： 【答案】x． 【解析】原式． 考點(diǎn)：分式的乘除法． 歸納5：分式的混合運(yùn)算 基礎(chǔ)知識(shí)歸納：在分式的

22、混合運(yùn)算中，應(yīng)先算乘方，再將除法化為乘法，進(jìn)行約分化簡(jiǎn)，最后進(jìn)行加減運(yùn)算．若有括號(hào)，先算括號(hào)里面的．靈活運(yùn)用運(yùn)算律，運(yùn)算結(jié)果必須是最簡(jiǎn)分式或整式． 注意問(wèn)題歸納：注意運(yùn)算順序，計(jì)算準(zhǔn)確． 【例8】化簡(jiǎn)： 【答案】． 考點(diǎn)：分式的混合運(yùn)算． ?1年模擬 1．（2015屆四川省成都市外國(guó)語(yǔ)學(xué)校中考直升模擬）要使有意義，則x應(yīng)滿足（ ） A．≤x≤3 B．x≤3且x≠ C．＜x＜3 D．＜x≤3 【答案】D． 【解析】 試題分析：由題意得，，解不等式①得，x≤3，解不等式②的，x＞，所以，＜x≤3．故選D． 考點(diǎn)：1．二次根式有意義的條

23、件；2．分式有意義的條件． 2．（2015屆山東省威海市乳山市中考一模）計(jì)算（-）-1=（ ） A．- B． C．-2 D．2 【答案】C． 【解析】 試題解析：．故選C． 考點(diǎn)：負(fù)整數(shù)指數(shù)冪． 3．（2015屆山東省濰坊市昌樂(lè)縣中考一模）分式的值為0，則（ ） A．x=-1 B．x=1 C．x=±1 D．x=0 【答案】B． 考點(diǎn)：分式的值為零的條件． 4．（2015屆廣東省深圳市龍華新區(qū)中考二模）化簡(jiǎn)的結(jié)果是（ ） A．-1 B．1 C．1+x

24、 D．1-x 【答案】A． 【解析】 試題分析：原式=．故選A． 考點(diǎn)：分式的加減法． 5．（2015屆江蘇省南京市建鄴區(qū)中考一模）計(jì)算a3?（）2的結(jié)果是（ ） A．a(chǎn) B．a(chǎn)5 C．a(chǎn)6 D．a(chǎn)8 【答案】A． 【解析】 試題分析：原式=a3?=a，故選A． 考點(diǎn)：分式的乘除法． 6．（2015屆河北省中考模擬二）已知a=，b=，則（）÷的值為（ ） A．1 B． C． D． 【答案】B． 考點(diǎn)：分式的化簡(jiǎn)求值．

25、7．（2015屆北京市平谷區(qū)中考二模）分式有意義的條件是 ． 【答案】a≠2． 【解析】 試題分析：根據(jù)分式有意義的條件可知分母a-2≠0，所以a≠2． 考點(diǎn)：分式有意義的條件． 8．（2015屆山東省聊城市中考模擬）若與（x+1）0都有意義，則x的取值范圍為 ． 【答案】x＞-1且x≠1． 【解析】 試題分析：根據(jù)題意得： 解得：x＞-1且x≠1．故答案為：x＞-1且x≠1． 考點(diǎn)：1．二次根式有意義的條件；2．分式有意義的條件；3．零指數(shù)冪． 9．（2015屆廣東省佛山市初中畢業(yè)班綜合測(cè)試）若分式的值為零，則x的值為

26、 ． 【答案】x=-1． 【解析】 試題分析：根據(jù)題意，得|x|-1=0，且x-1≠0，解得x=-1．故答案為：x=-1． 考點(diǎn)：分式的值為零的條件． 10．（2015屆江蘇省南京市建鄴區(qū)中考一模）在函數(shù)y=中，自變量x的取值范圍是 ． 【答案】x≠1． 【解析】 試題分析：根據(jù)題意得1-x≠0，解得x≠1．故答案為：x≠1． 考點(diǎn)：1．函數(shù)自變量的取值范圍；2．分式有意義的條件． 11．（2015屆北京市門頭溝區(qū)中考二模）已知，求的值． 【答案】1-． 考點(diǎn)：分式的化簡(jiǎn)求值． 12．（2015屆四川省成都市外

27、國(guó)語(yǔ)學(xué)校中考直升模擬）計(jì)算題 （1）先化簡(jiǎn)，再求值：，其中a=sin45°，b=cos30°； （2）若關(guān)于x的方程無(wú)解，求a的值． 【答案】（1） ；（2） a=1． 【解析】 試題分析：（1）原式第二項(xiàng)利用除法法則變形，約分后利用同分母分式的減法法則計(jì)算，約分得到最簡(jiǎn)結(jié)果，把a(bǔ)與b的值代入計(jì)算即可求出值； （2）分式方程去分母轉(zhuǎn)化為整式方程，由分式方程無(wú)解求出x的值，代入計(jì)算即可求出a的值． 試題解析：（1）原式=-（a-b）?=，當(dāng)a=sin45°=，b=cos30°=時(shí)，原式=； （2）去分母得：x2-ax-3x+3=x2-x，解得：x=，由分式方程無(wú)解，得到x（x-1

28、）=0，即x=0或x=1，若x=0，a無(wú)解；若x=1，解得：a=1． 考點(diǎn)：1．分式的化簡(jiǎn)求值；2．分式方程的解；3．特殊角的三角函數(shù)值． 13．（2015屆安徽省安慶市中考二模）先化簡(jiǎn)，再求值：（﹣）÷，其中x=． 【答案】，1﹣． 考點(diǎn)：分式的化簡(jiǎn)求值． 14．（2015屆山東省威海市乳山市中考一模）化簡(jiǎn)代數(shù)式，并判斷當(dāng)x滿足不等式組時(shí)該代數(shù)式的符號(hào)． 【答案】負(fù)號(hào)． 【解析】 試題分析：做除法時(shí)要注意先把除法運(yùn)算轉(zhuǎn)化為乘法運(yùn)算，而做乘法運(yùn)算時(shí)要注意先把分子、分母能因式分解的先分解，然后約分化簡(jiǎn)為；再分別求出一元一次不等式組中兩個(gè)不等式的解，從而得到一元一次不等式組的解集，

29、依此分別確定x+1＜0，x+2＞0，從而求解． 試題解析：原式==； 不等式組，解不等式①，得x＜-1．解不等式②，得x＞-2，∴不等式組的解集是-2＜x＜-1，∴當(dāng)-2＜x＜-1時(shí)，x+1＜0，x+2＞0，∴＜0，即該代數(shù)式的符號(hào)為負(fù)號(hào)． 考點(diǎn)：1．分式的化簡(jiǎn)求值；2．解一元一次不等式組． 15．（2015屆山東省日照市中考模擬）先化簡(jiǎn)，再求值：，其中， 【答案】-4． 考點(diǎn)：分式的化簡(jiǎn)求值． 16．（2015屆湖北省黃石市6月中考模擬）先化簡(jiǎn)再求值，已知a2+2a﹣7=0． 【答案】，． 考點(diǎn)：分式的化簡(jiǎn)求值． （英文版 ） easily blame, to p

30、revent the broken window effect. Supervise the leading cadres to play an exemplary role, take the lead in the strict implementation of the < code > and < rule >, lead to safeguard the solemnity and authority of the party discipline, ensure that the party discipline and the laws and regulations for i

31、mplementation in place. Throughout the discipline in the daily supervision and management , strengthen supervision and inspection, from the thorough investigation of violations of discipline behavior. Strengthen to key areas, key departments and key projects as well as the masses reflect the concen

32、tration of the units and departments for supervision. - strengthening supervision, discipline inspection and supervision of cadres to set an example for compliance with the < code > and < rule > is a man must be hexyl, blacksmith needs its own hardware. Discipline inspection organs as the executor o

33、f the party discipline, and supervisor of the defenders, for its supervision must be more strictly, discipline inspection and supervision of cadres to firmly establish the awareness of Party Constitution, sense of discipline and rules consciousness, politics loyalty, sense obey. Action speak Ji Ordi

34、nance to set an example of the regulations of the rule of law, strengthen supervision and accept the supervision of the firmness and consciousness, do comply with < > and < >. To firmly establish the discipline must first be disciplined, the supervisor will be subject to the supervision of "concept,

35、 and consciously safeguard and implement party compasses party, take the lead in practicing" three strict real strict, so loyal, clean, play. To be good at learning, the Constitution and the < code > as morality, politics and brought to fruition; to implement < >, do not want to, dare not, not with

36、disciplinary ruler to supervision; to discipline a ruler, often the control inspection, and consciously in the ideological red line to draw the row Ming Good accumulation is indeed the bottom line, so that the heart has fear, said to have quit, the line has ended. Attached: indifferent to heart, cal

37、mly to the table in our life, there are many unpredictable things will happen, some good, some bad things, we cannot control is powerless to stop, but with time, you will find in life sometimes turns out to be not good, some bad things finally turned out to be a good thing, but then we muddy however

38、 did not know, this is the life teach us things. 1, life can be complex, can also be simple. Want simple life of precipitation, to have enough time to reflect, to make Become more perfect. Life is the most important thing is not to win, but the struggle; not to have conquered, but to have fought wel

39、l. 2, the plain is the background of life. Live a plain life, give up on themselves is not a coward, but the wise answers; not disillusioned after the heart, such as ashes, but experience the storm after the enlightenment; not unrewarding perfunctorily, but calm attitude of life of unrestrained self

40、-confidence. Plain living, there is no noise noisy, no earthly troubles, more did not fill in the discontent of desire, some just a calm, a calm. 3, memory of heart will not good things to erase the, life is a When no movie, pain is a beginning, the struggle is a kind of process, death is a kind of

41、ending. Give up this giving up is the helpless, do not give up the abandoned, do not give up this giving up is ignorance, do not give up should not give up is persistent. 4, a thing figured is heaven, think impassability is hell. Since the living, to live better. Sometimes we because of too narrow-m

42、inded, too care around the chores and penny wise and pound foolish, not worth the candle. Some things to attract trouble and worry, completely depends on how we look at and deal with it. Don't always take everything back to things, and don't get into a blind alley, don't want to face, don't be narro

43、w-minded. Poke to care, is a kind of open-minded, a free and easy. 5, I am not afraid of others behind me a knife, I afraid to look back and see stab me, is my intention to treat people; I am not afraid of the truth to tell the best friend, I'm afraid he turned to it as a joke to tell don't 6, when

44、we are in a positive frame of mind, you will find many good things; and when we are in a negative state of mind, you will find many depressed things; life happy and worry, all is you of life attitude, optimistic, good luck; loss of sink, Eritrea company. When you are in adversity, may wish to change

45、 a point of view to think everything over to the good Think, because good mentality decided the fate of the! 7, people are tired, rest; heart tired, calm. Grow up, mature, this society read. Tired and sad, squat down, to their a hug. Because the world no one can sympathize with you, have mercy on yo

46、u. You cry, tears is your own; you pain, no one can understand. Then you only tears to smile. 8, each people have youth, Each youth are a story, the life of the world never gets easier, I want what, wish the world all know, as has been the same; now want anything, for fear that others know, or like

47、 to lose the same. 9, the heart move, everything in the world is followed by birth, Rangrang, important thing is often the most difficult to open one's mouth, because words will reduce its importance; to let strangers people care about your life in the good things, the original is not easy 10, do no

48、t blame, do not laugh at who, also don't envy who. Like a person is a kind of feeling, not like a person is true. The truth is easy to explain, I feel Is unspeakable. The best travel life is that you in a strange place found a long lost touched. 11, happy life not in the bustling in, and in the peac

49、e of mind; no matter how many grievances, how uncomfortable, and ultimately to heal themselves or their own, others may got you to comfort, but never know your heart is how wanjianchuanxin. 12, ma'am, like a movie, learn to appreciate, learn to be grateful, learn tolerance, and goodness, helping oth

50、ers. Instead of accusing the society, as into one; and an exception is better to give than to what 13, don't envy him A sum of, don't lose your life and the life, respectively is: the former is a we experienced cannot escape in a day finally will last minute, while the latter is our persistent, we w

51、ant to cherish the memory of those people and things. 14, learn to smile, learn to strong, the world you know so many people, so many people and you are, you cannot change also can't let everyone like you, so also do not want to do. Life is too short to go crazy to love to go to waste, to chase the

52、dream to regret. 15, when temper, a blessing to go. A wounding elegant people, the key is to control their own emotions. With the mouth is the most stupid behavior. A control negative emotions than a can take a city more powerful water flow slow, language is expensive. People spent two years of time

53、 to learn to speak, but to spend a few years time to shut up. That is a kind of ability, that is a kind of wisdom. 16, life is not perfect, sometimes, growth is not a cry, not an eyeful of tears, there is no trace of emotion, there is no gleam of hope, no desire, no action, no static, there is only

54、one kind of downward sinking feeling, sink A murky? 6? 7? 6? 7 sink? 6? 7? 6? 7 toward the bottom of the sink. 17, in some way, do not go, you will not know the other side scenery is beautiful. To you is not good, you do not mind too much, no one has an obligation to you; you learn knowledge, is you

55、 have weapons, you can start from scratch, but not unarmed; how do you treat people, does not represent how others treat you, if cannot see through this point, only inviting worry. 18, time is like a sponge in the water, as long as you are willing to squeeze, the total water is still there. Every li

56、fe, after the ups and downs The best test of live, to life, survival and continuation, do not stop the struggle in the joys and sorrows of life on the road, so that different soul to bear life beat, acceptance of suffering. 19, indifferent to heart, calmly in table, elegant and comfortable life, do

57、not take what is so important. The pursuit will be disappointed; to be alive, you will have trouble. Life is the most afraid of what all want to care about, but also what all grasp is not firm, without scenery, separated populations, such as not to desire, all docked in the fate of the end. Why is t

58、oo rigid, the natural, to go stay not to live, let go of obsession, revel is 20, if the fate of the broken Hopes of sailing, please don't despair, the coast is still, if the fate of the withered petals of the beautiful, please do not sink, the spring is still, life will always be endless trouble, pl

59、ease don't helpless, because they are still alive, is still a dream, the sun still, we still. Lost, keep memories; to get, must work to; but the most important is good to cherish their own. 21, life, select the complex, is to choose the pain; choose a simple, is choose to be happy. The complex world

60、 like a Significance of pride. Hope is the ornate palace, outside people admiring the magnificent, living in the deep knowledge of living it to pay the price. Simple world as a simple log cabin outside ridiculed shabby, the heart is willing to go live to know the joy. Suffering and joy is their own

61、 choice. 22, learn how to use a single powerful heart, let the past be the past, let the future come. Life is really the end of the end of an eagle is flying wings, life is constantly pursuit. Don't miss to regret, don't wait for old just miss. Time to return, seize every moment, again painstakingly

62、 again tired also Those struggling to fly. 23, life could not Yimapingchuan, even flat pavement, inevitably there will be a few pieces of roadblocks. Some of the rocks around the past, while others have to move it out. Just move others put the stone is very easy, because the stone from the appearanc

63、e we can discern; difficult to myself to move away the heart of stone head. Leave time to spend with her, often reflect my heart, so as to remove your heart of stone. 24, everything does not have to be demanding, come to, everything does not have to care about, over the past; failing to do not frown

64、, laugh it laugh. Results Don't demand, do to; life is a simple, calm and peaceful. Always not to choose their own path and regret, life is like a train, the scenery and then the United States will retreat, the passage of time and encounter will eventually drifting further and further away, before i

65、s always himself. 25, everyone has a weakness, weakness is true humanity. That has no weakness, a shallow person. That people think there is no weakness, mostly false. Life has shortcomings, there are shortcomings is the real life. That no one regret, or childish or numbness or Self deception. It is

66、 in tolerance of weakness and so on to accept, people live happily. Hello, everyone! I am a party member. The title of my speech is: < study and implement the party's two laws, doing practical play highway. 2015 October 18, the Central Committee of the Communist Party of China promulgated the implementation of the < the probity of the Communist Party of China self-discipline criterion > and < Chinese Communist Party discipline and punishment regulations. We Heyuan male passers-by to respond p