问题 填空题
化简:
2x-2
1-x2
=______; 
4m2-3mn
mn
-
3m2+2mn
nm
=______.
答案

2x-2
1-x2
=
2(x-1)
-(x+1)(x-1)
=-
2
x+1

4m2-3mn
mn
-
3m2+2mn
nm

=

4m2-3mn-3m2-2mn
mn

=

m2-5mn
mn

=

m-5n
n

故答案为:-

2
1+x
m-5n
n

单项选择题
单项选择题