Question 178393
 {{{x^2 - 8x + c}}}
To complete the square, The rule is to take 1/2 of the
coefficient of {{{x}}} and square it, so
{{{c = (-8/2)^2}}}
{{{c = 16}}} answer
{{{x^2 - 8x + 16}}}
{{{x - 4)^2}}}