34.分式的加减(提高)巩固练习

1、【巩固练习】一.选择题1.下列运算中,计算正确的是（）A.丄+丄2a 2b2(a +b)B.b b+-a c2bacc.caa a2a2. a+b+b七的结果是4B.-aD.C.3.下列计算结果正确的是（A.x+2 x-2 (x+2)(x-2)B.-2x2C.D.-b2a-b2 2X -y3x26X2yx-15y7=(x2y2)(y2X2)12xy-3x22y2 X 一9 3-xX+34.下列各式中错误的是（c-d c+d c-d-c-d-2dA.B.D.X - y y -X5.下列计算正确的是（A X T 1-XA. -=2B.C.A.01 -X X T4(X-1)“ 3“3(mT )(1

2、m )a -2b +3c a-b +c 丄 Ia +b -cB.1D.二.填空题+ =0 b a2a +52a+5(X-1)2l-x)4(x+1)(x 2)X2D.m=1(1-X)2-x + 2(x+1)(x-2)2c -b旦的结果是(a c +b c a -bC.D.2(b-2c)c-a -b6.化简7.分式一-一,一-一的最简公分母是a(m+2) b(m+2)ab11a、b为实数，且ab = 1，设P= 亠+ +亠，则P.a+1 b+1a + 1 b+1Q(填“>”、9.“V” 或“=”).2a1 1+ 2a+1a 1 a -110.2a 1 a2 _4111.若 x < 0,

3、则一-12.已知 ab =1,三.解答题13.计算下列各题3|x| |x-3|a+1 b+1+ 2a+1522a+33-2a 4a -914等式8x +9AB=+”对于任何使分母不为2x + x-6 x+3 x-215.阅读并计算:例：计算:2x +4x3-x 1 +x1+x21+x40的x均成立，求A、B的值.1 +:+x(x+1) (x+1)(x+2)(x+2)(x+3)原式一丄Jx+1 x + 2x X +1x+2 x+3x x+3x(x +3)仿照上例计算:x(x+2) (x+2)(x+4) (x+4)(x+6)【答案与解析】一.选择题1.【答案】【解析】D；丄+2.【答案】2a 2b

4、C；【解析】a +b +a +bb 丄 b bc + ab I = ba2ab a cac(a+bWb)a2b2a -ba -ba-ba23.【答案】C；11.【答案】4.5.6.【解析】【答案】【解析】【答案】【解析】【答案】【解析】二.填空题7.【答案】8.【答案】【解析】9.【答案】【解析】10.【答案】【解析】【解析】X +2X-2(x+2)(x 2)X22-yX -15X2 9C;3 -xx-152(x +3)y -XC;X11-x(x+g2)2 2y -X2x-9 (x-3)(x+3)X +3X2 -x + 22 2(X -x-2)(x -x+2)A；原式=P-Q0；a+1a+22

5、ax+14(I).4，一1)a-2b+3c a-b+ca-1 丄 b-1=十a+1 b+1a12aX2 X 22c-ba + b-cX2x + 22(ab 1)a2 1(a+12 + 1 )a-1+a+1-2aa2 12a-(a +2 )(a + Ub + 1)=0.2a-42-aa2 4a +22xX2 92x3|x| |x3|2cX -912.【答案】1；【解析】三.解答题13.【解析】a +1b+1 a+ab b+ab 1+b 1+a1 + a +1 +b1 + a + b + ab解：(1)原式(2)原式14.【解析】解:8x+9+ x 6所以(1 + a )(1 +b)1 + a + b + ab2a +1522a+3 2a-3 4a -92x2x-X2X +3lA + B =813B -2A=915.【解析】解：原式x+2x+61+x2-4x3X -21+x42( 2a - 3 ) 3(2a +3 )+ 2a +1524a -94x3