SAT Question 5ae186b4: Nonlinear Equations In One Variable And Systems Of Equations In Two Variables answer and explanation with Desmos solution

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.