Question

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

{−3x+4y=−20
y=x−4




(−2, −6)

(0, −5)

(−4, −8)

(4, 8)

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.