解方程2X-1.8=X+2.4 3X-2(10-X)=15 (2X+3)*2=5X-4 18/4X-3=9 (4-X)*
2个回答

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