SAT Question 346d5c2e: Linear Functions answer and explanation with Desmos solution

Choice A is correct. Substituting $63$ for $f(x)$ in the given function yields $63=9(2x+3)$. Dividing both sides of this equation by $9$ yields $7=2x+3$. Subtracting $3$ from both sides of this equation yields $4=2x$. Dividing both sides of this equation by $2$ yields $2=x$. Therefore, $f(x)=63$ when the value of $x$ is $2$.