Question

Which ordered pair is the solution to the system of equations?

Answer 1

$\begin{cases}-3x+4y=-20\\y=x-4\end{cases}\\\\\\-3x+4(x-4)=-20\\\\-3x+4x-16=-20\\\\x-16=-20\quad|+16\\\\x-16+16=-20+16\\\\\boxed{x=-4}\\\\\\y=x-4\\\\y=-4-4\\\\\boxed{y=-8}$

Answer C.