Explicação passo-a-passo:
a)
12 - 2x = 0
-2x + 12 = 0
-2x = 0 - 12
-2x = -12
x = -12/-2
x = 6
b)
-9 - 3x = 0
-3x - 9 = 0
-3x = 0 + 9
-3x = 9
x = 9/-3
x = -3
c)
6x + 32 = 38
6x + 32 = 38
6x = 38 - 32
6x = 6
x = 6/6
x = 1
d)
2x + 2 - 3 = 7
2x - 1 = 7
2x = 7 + 1
2x = 8
x = 8/2
x = 4
