第2个回答 2012-07-25
2X-1.8=X+2.4
2X-X=2.4+1.8
X=4.2
3X-2(10-X)=15
3X-20+2X=15
5X=15+20
5X=35
X=7
(2X+3)*2=5X-4
4X+6=5X-4
6+4=5X-4X
X-10
18/4X-3=9
18/4X=9+3
18/4X=12
X=12* 4/18
X=4/3
(4-X)*7=(X-4)*9
28-7X=9X-36
28+36=9X+7X
64=16X
X=4
6.2*(3X-4)+7*(4-X)=4X
18.6X-24.8+28-7X=4X
18.6X-7X-4X=24.8-28
7.6X=-3.2
X=- 3.2/7.6
X=- 8/19