2X-1.8=X+2.4
2X-X=2.4+1.8
X=4.2
3X-2(10-X)=15
3X-20+2X=15
3X+2X=15+20
5X=35
X=7
(2X+3)*2=5X-4
4X+6=5X-4
4X-5X=-4-6
-X=-10
X=10
18/4X-3=9
18-12X=36X
36X+12X=18
48X=18
X=8/3
(4-X)*7=(X-4)*9
28-7X=9X-36
9X+7X=28+36
16X=64
X=4
2*(3X-4)+7*(4-X)=4X
6X-8+28-7X=4X
6X-7X-4X=8-28
-5X=-20
X=4