x = 3 y = 15 - x 2 A solution to the given system of

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 $\left(3\right)\left(144\right)$, or $432$. Therefore, the value of $xy$ is $432$.

Choice B is incorrect and may result from conceptual or calculation errors.

Choice C is incorrect and may result from conceptual or calculation errors.

Choice D is incorrect and may result from conceptual or calculation errors.