Solve x2 + 4x – 4 = 8 for x. A) = –12 or x = 2 B)x = –11 or x = 1 C)x = –2 or x = 12 D)x = –1 or x = 11

Respuesta :

hello : 
x² + 4x – 4 = 8
x²+4x -12 = 0
(x²+2(2)(x)+2²)-2² -12 =0
(x+2)² -16 = 0
(x+2)² = 4²
x+2 = 4  or x+2 = -4 
x=2    or x= -6