问题
解答题
| 分式的计算： ①
②
③a-2b2（a2b-2）-3 ④
⑤
⑥(
|
答案
①原式=
-a (a+b)(a-b) a-b (a+b)(a-b)
=a-(a-b) (a+b)(a-b)
=
；b (a+b)(a-b)
②原式=
+b2 a-b
+a2 a-b (a+b)(a-b) a-b
=a2+b2+(a2-b2) a-b
=
；2a2 a-b
③原式=a-2 b2•a-6 b6
=a-8 b8；
④原式=
÷[3-x 2(x-2)
-(x+2)(x-2) x-2
]5 x-2
=
÷3-x 2(x-2) x2-4-5 x-2
=
÷3-x 2(x-2) (x+3)(x-3) x-2
=
•3-x 2(x-2)
=-2(x-2) (x+3)(x-3)
；1 x+3
⑤原式=
-3b-a (a+b)(a-b) (a+2b)(a+b) (a+b)(a-b)
=3b-a-(a2+ab+2ab+2b2) (a+b)(a-b)
=
；3b-a-a2+3ab-2b2 (a+b)(a-b)
⑥原式=4a-2 b2•
a-2 b21 2
=2a-4 b4
=
．2b4 a4