问题 解答题
化简:
(1)(xy-y2
x2-2xy+y2
xy
x-y
x2

(2)
a-1
a-2
÷
a2-2a+1
2a-4
答案

(1)原式=y(x-y)•

xy
(x-y)2
x-y
x2
=
y2
x

(2)原式=

a-1
a-2
2(a-2)
(a-1)2
=
2
a-1

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