Answer
Only $x=-1$ is a solution of the given equation.
Work Step by Step
Substitute each value of $x$ into the equation. If the resulting equation is true, then the number is a solution of the given equation.
$\text(a)$ Substitute $-1$ to $x$:
$\begin{align*}
x-8&=-9\\
-1-8&=-9\\
-9&=-9
\end{align*}$
Thus, $x=-1$ is a solution of the given equation.
$\text(b)$ Substitute $2$ to $x$:
$\begin{align*}
x-8&=-9\\
2-8&=-9\\
-6&\not=-9
\end{align*}$
Thus, $x=-1$ is a solution of the given equation.
