(完整版)八年级数学上学期易错计算题专练(精心整理)含答案,推荐文档

一．计算

八年级数学易错计算题专练

1、-66 ? (-6)6

2、(-p2 )3

3、(4 ?104 ) ? (3?102 )

4 、a

5 ÷a2 ÷(-a2 ) 5、(-1

x2 y3 )? (-

x2 y)

3 2

6、(6x - 4)(3x + 2)

7、(4x3 y + 6x2 y2 -xy3 ) ÷

2xy (-7xy2 )2 ? ( 1

x2 y -y2 )

7 8、40

2 1

?39 （简便计算）9、

3 3

10、 (m -n)(m +n) 11、 (2m - 3n)212、(-a -b)(-a +b) 13、 (a +b -c)(a -b +c) 14、(a -b -c)2

15、 (x - 2)(x + 2)(x2 + 4) 17、 (3a - 4b + 2c)216、(-x + 2 y)2

18、已知a +

= 5 ,求a4 +

的值

a a4

19、已知a +b = 4 , a2 +b2 =11 ,求(a -b)2 20、已知x a = 3, x b = 2 ,求x2a+b

二、分解因式：

（1）a 2 (x -1) +b 2 (1-x) （2）(m2 +n 2 )2 - 4m2n 2 （3）x 4- 16（4）6xy -x 2 - 9 y2 （5）

(x +y)2 -10(x +y)+ 25 （6）- 16 + 9x 2

（7）(m +n)2 - 4n 2（8）a2 -b2 +4b -4 （9）. x 2 - 4xy - 1 + 4 y 2

10.下列各式从左到右的变形是因式分解的是（）.

A. x 2 + 2x + 3 = (x + 1)2 + 2

B. (x +y)(x -y) =x 2 -y 2

C. x2－xy＋y2＝(x－y)2

D. 2x - 2 y = 2(x -y)

三、计算

解方程(一定要检验）（1）

12 (2) 1

x -1

=-3 x + 3 3 -x x2 - 9 x - 2 2 -x

（3）计算

a -1

-a -1

答案

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