b) 2(3x + 7) + x = 70
6x + 14 + x = 70
6x + x = 70 - 14
7x = 56 |:7
x = 8
c) 4x - 6 = x + 9
4x - x = 9 + 6
3x = 15 |:3
x = 5
d) 4(x + 3) = 2(x - 6)
4x + 12 = 2x - 12
4x - 2x = -12 -12
2x = -24 |:2
x = -12
f) -3x + 6 = 8 - x
-3x + x = 8 - 6
-2x = 2 |:(-2)
x = -1