Answer
The solution set is: $\left\{-2, \frac{4}{3}\right\}$.
Work Step by Step
Subtract $8$ to both sides:
$3x^2+2x-8=0$
Factor the trinomial:
$(3x-4)(x+2)=0$
Equate each factor to zero then solve each equation:
$3x-4 = 0 \text{ or } x+2 = 0
\\3x=4 \text{ or } x=-2
\\x =\frac{4}{3} \text{ or } x = -2$
