0,5(x - 12) = 3.5x + 2;

0.5x - 0.5 * 12 = 3.5x + 2;

0.5x - 6 = 3.5x + 2;

0.5x - 3.5x = 2 + 6;

-3x = 8;

x = -2 2/3.