SAT Question 0bebc08c: Nonlinear Equations In One Variable And Systems Of Equations In Two Variables answer and explanation with Desmos solution

Choice A is correct. The first equation in the given system of equations is $x=3$. Substituting $3$ for $x$ in the second equation in the given system of equations yields $y={\left(15-3\right)}^2$, or $y=144$. Substituting $3$ for $x$ and $144$ for $y$ in the expression $xy$ yields $(3)(144)$, or $432$. Therefore, the value of $xy$ is $432$.