Variable $x$ cannot be equal to any of the values $-4,4$ since division by zero is not defined. Multiply both sides of the equation by $\left(x-4\right)\left(x+4\right)$, the least common multiple of $x+4,x-4,x^{2}-16$.
$$x-4+\left(x+4\right)\times 3=3x+8$$
Use the distributive property to multiply $x+4$ by $3$.
