First, set up the problem.
Second, rewrite the actual value as two new equations. (one of each sign, +,-)
Then, solve the equation for u and that's how you get the final answer.
[tex]|4u + 16| = 12 \\ 4u + 16 = 12 \\ 4u + 16 = - 12 \\ u = - 1 \\ u = - 7 \\ u1 = - 7 \\ u2 = - 1[/tex]
