Answer
$(a)$ $-2$
$(b)$ $4$
Work Step by Step
$x^{2}-5x-2$
$(a)$ $x=0$
Replace $x$ with $0$ and evaluate the indicated operations:
$(0)^{2}-5(0)-2=-2$
$(b)$ $x=-1$
Replace $x$ with $-1$ and evaluate the indicated operations:
$(-1)^{2}-5(-1)-2=1+5-2=4$