0.4 (2x + 1/2) = 3 [0.2x+(-2)] - 4
0.4 (2x + 1/2) = 3(0.2x-2) - 4
Then, you have to use the distributive property.
0.8x + 0.2 = 0.6x - 6 - 4
0.8x + 0.2 = 0.6x - 10
0.8x - 0.6x + 0.2 = -10
0.2x + 0.2 = -10
0.2x = -0.2 - 10
0.2x = -10.2
x = -10.2/0.2
x = -51
Does that make sense?