Answer
$$x=-2$$
Work Step by Step
$$[(3+6)^2\div{3}]\cdot 4=-54x$$
Simplify the left side of the equation by working on the terms inside the parentheses:
$$[(3+6)^2\div{3}]\cdot 4$$ $$=[(9)^{2}\div3]\cdot 4$$ $$=[81\div3]\cdot 4$$ $$=27\cdot 4$$ $$=108$$
Rewrite the equation:
$$108 = -54x$$
Divide both sides by $-54$:
$$x = -2$$
