问题 解答题
计算:
(1)-3mn÷
2n2
3m

(2)
x2-2x+1
x2-1
÷
x-1
x2+x

(3)
2m-6
4-4m+m2
m2+6m+9
3-m
答案

(1)原式=-3mn•

3m
2n2

=-

9m2
2n

(2)原式=

(x-1)2
(x+1)(x-1)
x(x+1)
x-1

=x;

(3)原式=-

2(m-3)
(m-2)2
(m+3)2
m-3

=-

2(m+3)2
(m-2)2

单项选择题
单项选择题