Question

Solve the inequality |4x +4| < 12

Answer 1

Start by dividing all terms by 4, to reduce this expression: |x+1| < 3.

Case 1: x+1 is already positive. The abs. val. operator does not change

anything. Then x+1<3, or x<2.

Case 2: (x+1) is negative. The abs. val. operator, in effect, puts a - sign in

front of (x+1): -(x+1)<3. Distributing the - sign: -x - 1 < 3. Adding 1 to both sides: -x < 4. We want to solve for positive x, so we mult. both sides of

-x<4 by -1 AND change the direction of the inequality symbol:

x > -4

Thus, the solution set is (-4,2): All real numbers between -4 and 2.

Answer 2

$|4x +4| < 12\\\\ 4|x+1|$