SOLUTION: please help... have to solve by completing square 2r^2+10r+11=0

Question 267495: please help... have to solve by completing square
2r^2+10r+11=0
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
solve by completing square
2r^2+10r+11=0
Rearrange:
2r^2 + 10r = -11
Factor left side:
2(r^2 + 5r + ?) = -11 + 2?
Complete the square:
2(r^2+5r + (5/2)^2) = -11 + 2(5/2)^2
Factor:
2(r+(5/2))^2 = -22/2 + 25/2
2(r+(5/2)^2 = 3/2
(r+5/2)^2 = 3/4
Take the square root:
r + 5/2 = +-sqrt(3)/2
Solve for "r":
r = (-5+-sqrt(3))/2
Cheers,
Stan H.
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