Resposta :
a) x + 5 = 8
x = 8 - 5
x = 3
b) x + 6 = 4
x = 4 - 6
x = -2
c) x - 35 = -57
x = -57 + 35
x = -22
d) 3x = 12
x = 12/3
x = 4
e) 3x - 4 = 2x + 8
3x - 2x = 8 + 4
x = 12
f) 6x = 2x + 16
6x - 2x = 16
4x = 16
x = 4
g) 5x + 4 = x - 4
5x - x = -4 - 4
4x = -8
x = -2
h) -x/3 = 7
x = -21