Answer
Only $x=2$ 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 $x$:
$\begin{align*}
x+4&=3x\\
-1+4&\stackrel{?}{=}3(-1)\\
3&\not=-3
\end{align*}$
Thus, $x=-1$ is NOT a solution of the given equation.
$\text(b)$ Substitute $2$ to $x$:
$\begin{align*}
x+4&=3x\\
2+4&\stackrel{?}{=}3(2)\\
6&\stackrel{\checkmark}{=}6
\end{align*}$
Thus, $x=2$ is a solution of the given equation.
