Answer
66
Work Step by Step
$x^{2}+5x$ for $x=6$, substitute 6 for each x in the expression
$6^{2}+(5\times6)$, then using order of operations, simplify exponents first
$36+(5\times6)$, then multiplication and division in the order they come
$36+30$, then add or subtract in the order they come
$66$