Variable $a$ cannot be equal to $-\frac{3}{4}$ since division by zero is not defined. Multiply both sides of the equation by $5\left(4a+3\right)$, the least common multiple of $-3-4a,5$.
$$-5\left(3a+7\right)=4a+3$$
Use the distributive property to multiply $-5$ by $3a+7$.
