SOLUTION: solve equation by completing the square x2 + 4x - 36 = 0

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Question 451619: solve equation by completing the square
x2 + 4x - 36 = 0
Found 2 solutions by ewatrrr, nerdybill:
Answer by ewatrrr(24785) About Me  (Show Source):
You can put this solution on YOUR website!
 

Hi

completing the square

x2 + 4x - 36 = 0

 (x+2)^2 - 4 - 36 = 0

   (x+2)^2 = 40

    x+2 = ± sqrt%2840%29 = ±sqrt%284%2A10%29

     x = -2 ±2sqrt%2810%29

Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
x^2 + 4x - 36 = 0
x^2 + 4x = 36
half 'b' and square it -- then add to both sides
x^2 + 4x + 4 = 36 + 4
(x+2)(x+2) = 40
(x+2)^2 = 40
x+2 = sqrt(40)
x+2 = sqrt(2*2*2*5)
x+2 = 2*sqrt(2*5)
x+2 = 2*sqrt(10)
x = 2*sqrt(10) - 2
x = 4.325