SAT Question be1b8c74: Nonlinear Equations In One Variable And Systems Of Equations In Two Variables answer and explanation with Desmos solution

Choice B is correct. To express $a$ in terms of $b$ and $x$, the given equation can be rewritten such that $a$ is isolated on one side of the equation. Since it's given that $b$ is a positive number, $b+9$ is not equal to zero. Therefore, dividing both sides of the given equation by $8\left(b+9\right)$ yields the equivalent equation $\frac{x}{8\left(b+9\right)}=a$, or $a=\frac{x}{8\left(b+9\right)}$.