Completing the square

Question

x^2+2x-19 solve Quadratic Equation by completing the square.

Answer 1

x^2 + 2x -19 = 0

x^2 +2x = 19

take half the x term's coefficient and square it, then add that result to both sides

half of 2 is 1.

square 1 to get 1,

add 1 to both sides

x^2 +2x + 1 = 19 +1

(x+1)^2 = 20

take the square root of both sides

x+1 = + or - sqr20 = + or - 2sqr5

x =-1 + 2sqr5