# Thread: Complete the square on:

1. ## Complete the square on:

Complete the square on:
x^2 - 8x
and
x^2 + 4k

Thanks

2. Originally Posted by icesta1
Complete the square on:
x^2 - 8x
and
x^2 + 4k

Thanks
You have to add and subtract the square of half of your coefficient of $x$.

So $x^2 - 8x = x^2 - 8x + (-4)^2 - (-4)^2$

$= \left(x - 4\right)^2 - 16$.

$x^2 + 4k$ is already complete as the coefficient of $x$ is $0$.