Answer
The solutions of the system are $(7, 114)$ and $(-6,-42)$
Work Step by Step
$y-30=12x
\rightarrow y=12x+30$
$y=x^2+11x-12$
Substitute $12x+30$ for y
$12x+30=x^2+11x-12$
$x^2-x-42=0$
$(x-7)(x+6)=0$
$x-7=0$ or $x+6=0$
$x=7$ or $x=-6$
Find corresponding y-values. Use either original equation
$y=12x+30$
$y=12(7)+30$ or $y=12(-6)+30$
$y=114$ or $x=-42$
The solutions of the system are $(7, 114)$ and $(-6,-42)$.
