Answer
$9$
Work Step by Step
With an expression that has the form $x^2 + bx$, add $(\frac{b}{2})^2$ to complete the square:
In the expression $x^2 - 6x$, $b$ is $-6$; therefore, $(\frac{b}{2})^2$ is:
$(\frac{-6}{2})^2$
Simplify the fraction:
$(-3)^2$
Evaluate the exponent:
$9$
