Answer
$x=29$
Work Step by Step
$$\begin{align*}
-3(3)+(-3)(x)+4(x)-4(6)&=-4 &\text{Apply the Distributive Property}\\
-9-3x+4x-24&=-4 &\text{Simplify.}\\
x-33&=-4 &\text{Combine like terms.}\\
x-33+33&=-4+33 &\text{Add 33 to both sides.}\\
x&=29&\text{Simplify.}
\end{align*}$$
Check the answer by substituting $29$ to the variable in the given equation.
$$\begin{align*}
-3(3+x)+4(x-6)&=-4\\
-3(3+29)+4(29-6)&\stackrel{?}{=}-4\\
-96+92\stackrel{?}{=}-4\\
-4&\stackrel{\checkmark}{=}-4
\end{align*}$$
Thus, the solution is $x=29$.
