A) -3.6x + 0.8 = -6.4
-3.6x = -6.4 - 0.8
-3.6x = -7.2
x = -7.2 / -3.6
x = 2

B) 6(3x - 0.7) = 4.8
18x - 4.2 = 4.8
18x = 4.8 + 4.2
18x = 9
x = 9 / 18
x = 0.5