Question

Solve the equation by completing the square. Round to the nearest hundredth if necessary. x2 – 4x = 12

Answer 1

x^2 - 4x = 12

(-4/2)^2 = 4

x^2 - 4x + 4 = 12 + 4

x^2 - 4x + 4 = 16

(x - 2) (x - 2) = 16

(x - 2)^2 = 16

To get rid of the exponent, square root both sides.

x - 2 = ± √16

x ± 2 √16

x = 2 + 4 x = 2 - 4

x = 6, x = -2