#### Answer

x=-$\frac{5}{3}$ or 3

#### Work Step by Step

Rewrite the equation in standard form.
3x$^2$=15+4x
3x$^2$-4x=15
3x$^2$-4x-15=0
Factor the trinomial.
(3x+5)(x-3)=0
Set each variable factor as equal to zero and then isolate the variable to find the solutions.
3x+5=0 or x-3=0
3x=-5 or x=3
x=-$\frac{5}{3}$ or x=3
Enter the original equation into your graphing utility to observe that the graph crosses the x-axis at -$\frac{5}{3}$ and 3.