Nonlinear equations in one variable and systems of equations in two variables SAT question

The correct answer is $-9$. Since $w$ is in the denominator of a fraction in the given equation, $w$ can't be equal to $0$. Since $w$ isn't equal to $0$, multiplying both sides of the given equation by $w$ yields an equivalent equation, $-54=6w$. Dividing both sides of this equation by $6$ yields $-9=w$. Therefore, $-9$ is the solution to the given equation.