1:
3x+15=8x-20
3x-8x=-20-15
-5x=-35
x=7
2:
-6x-8=-8x+13
-6x+8x=13+8
2x=21
x=10.5
3:
1/2x+18=1/6x-9
18+9=1/6x-1/2x
1/6x-1/2x=27
1/6x-3/6x=27
-2/6x=27
-x=81
x=-81
1:
3x+15=8x-20
3x-8x=-20-15
-5x=-35
x=7
2:
-6x-8=-8x+13
-6x+8x=13+8
2x=21
x=10.5
3:
1/2x+18=1/6x-9
18+9=1/6x-1/2x
1/6x-1/2x=27
1/6x-3/6x=27
-2/6x=27
-x=81
x=-81