Question

Solve the quadratic equation by completing the square.
x^2 + 4x - 3 = 0

A) x = 4 ± 7
B) x = 2 ± 7
C) x = -4 ± 7
D) x = -2 ± 7

Answer 1

$x^2+4x-3=0\\(x^2+4x+4) -3-4=0\\(x+2)^2=7\\x+2=\pm\sqrt{7}\\x=-2\pm\sqrt{7}$

The appropriate choice is

... D) x = -2 ±√7