先化简,再求值: 3-m 2m-4 ÷(m+2- 5 m-2 ) ,m= 2 -3

先化简,再求值: 3-m 2m-4 ÷(m+2- 5 m-2 ) ,m= 2 -3.
2025-05-15 04:22:16
推荐回答(1个)
回答1:

原式=
-(m-3)
2(m-2)
÷
(m+3)(m-3)
m-2

=
-(m-3)
2(m-2)
×
m-2
(m+3)(m-3)

=-
1
2(m+3)

当m=
2
-3时,原式=-
2
4