2-18+8х=10х-8
8х-10х=-8-2+18
-2х=8
Х=-4
<span>3(x +5)=7-5x ,
3x + 15 = 7 - 5x
3x + 5x = 7 - 15
8x = - 8 / : 8
x = - 1
4(x-9)=3(x-8) ,
4x -36 = 3x - 24
4x -3x = - 24 + 36
x = 12
7(3-2x)=15(1-x)
21 - 14x = 15 - 15x
-14x + 15x = 15 - 21
x = - 6
</span>
540:х=260-170
540:х=90
х=540:90
х=6
х:40=115-100
х:40=15
х=40*15
х=600