Question 337675
{{{x^2+2x}}}
To complete the square take ({{{1/2}}}) of the {{{x}}} coefficient, square it, then add and subtract this value to the expression.
{{{(1/2)(2)=1}}}
{{{1^2=1}}}
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{{{x^2+2x=x^2+2x+1-1}}}
{{{x^2+2x=(x^2+2x+1)-1}}}
{{{x^2+2x=(x+1)^2-1}}}