solve 2x2 12x − 14 = 0 by completing the square. 2(x 6)2 = 26; x = −6 square root 13, x = −6 − square root 132(x 6)2 = 20; x = −6 square root 20, x = −6 − square root 202(x 3)2 = 32; x = 1, x = −72(x 3)2 = 32; x = 13, x = 19