Answer
The solution set is $\left\{-4, 1\right\}$.
Work Step by Step
Subtract $4$ on both sides to obtain:
$x^2+3x-4=0$
We factor to obtain:
$(x+4)(x-1)=0$
Use the Zero-Product Property by equating each factor to zero.
Then, solve each equation to obtain:
$\begin{array}{ccc}
&x+4 = 0 &\text{ or } &x-1=0
\\&x=-4 &\text{ or } &x=1
\end{array}$
Thus, the solution set is $\left\{-4, 1\right\}$.
