SOLUTION: what quantity should be added to both sides of this equation to complete the square? x(2)-8x=5

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Question 259932: what quantity should be added to both sides of this equation to complete the square?
x(2)-8x=5
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
x^2-8x=5
take 1/2 of the coefficient of x
8/2=4 and square it
4^2=16
add 16 to complete the square
x^2-8x+16=21
(x-4)^2=21
|x-4|=+\-21
x-4=21
x=25
x-4=-21
x=-17
x=25