Solve 2x2 8x - 12 = 0 by completing the square. show step-by-step solution

Group x terms

(2x^2+8x) - 12=0

undistribute 2

2 (x^2+4x) - 12=0

take 1/2 of 4 and square it, add negative and positive of it insde (2^2=4)

2 (x^2+4x+4-4) - 12=0

factor perfect square

2 ((x+2) ^2-4) - 12=0

distribute

2 (x+2) ^2-8-12=0

2 (x+2) ^2-20=0

add 20 to both sides

2 (x+2) ^2=20

divide both sides by 2

(x+2) ^2=10

sqrt both sides, remember to take positive and negative root

x+2=+/-√10

minus 2 both sides

x=-2+√10 and - 2-√10