SOLUTION: How do you solve this problem by completing the square? r^2 + 6r - 8 = 0

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Question 431928: How do you solve this problem by completing the square?
r^2 + 6r - 8 = 0
Found 2 solutions by mananth, nerdybill:
Answer by mananth(16946) About Me  (Show Source):
You can put this solution on YOUR website!
r^2+6r=8
r^2+6r+9 = 8+9
(r+3)^2=17
take the square root
(r+3)= +/-+sqrt%2817%29
r= -3++sqrt%2817%29
r= -3-+sqrt%2817%29

Answer by nerdybill(7384) About Me  (Show Source):
You can put this solution on YOUR website!
r^2 + 6r - 8 = 0
r^2 + 6r = 8
take 1/2 of 6, square the result and add to both sides:
r^2 + 6r + 9 = 8 + 9
r^2 + 6r + 9 = 17
(r+3)(r+3) = 17
(r+3)^2 = 17
r+3 = sqrt%2817%29
r = sqrt%2817%29+-+3