Question

Explain how you can solve the pair of equations by substitution. Show all steps and write solution in (x, y) form.

Answer 1

$\bf \begin{cases} \boxed{y}=x+4\\ y=-2x-2\\ ---------\\ \boxed{x+4}=-2x-2 \end{cases} \\\\\\ 3x=-6\implies x=\cfrac{-6}{3}\implies x=-2 \\\\\\ \stackrel{\textit{if we plug that "x" in the first equation}}{y=(-2)+4\implies y=2}\qquad \qquad \qquad\qquad \qquad (\stackrel{x}{-2}~,~\stackrel{y}{2})$