SOLUTION: what number should be added to complete the square of the expression? x^2 + 2/5x

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Question 535913: what number should be added to complete the square of the expression?
x^2 + 2/5x
Answer by KMST(5328) About Me  (Show Source):
You can put this solution on YOUR website!
In the square of a monomial, you have the square of each term and the double product, so
%28x%2Ba%29%5E2=x%5E2%2B2ax%2Ba%5E2
has the squares of x and a
along with twice their product 2ax
x%5E2+%2B+%282%2F5%29x has the square of x
and the twice the product of x and what?
I would say it's
%282%2F5%29x=2%281%2F5%29x
so it's twice the product of x and 1%2F5
To complete the square of x%2B1%2F5
you need %281%2F5%29%5E2=1%2F25}
%28x%2B1%2F5%29%5E2=x%5E2%2B+%282%2F5%29x%2B1%2F25