## Algebra 1: Common Core (15th Edition)

$(-6,-7)$
Step 1 Substitute $y$ with $2x+7$ in the second equation and solve for x $2x+7=x+1\quad$ ... add $-x-7$ to both sides $2x-x=1-7$ $x=-6$ Step 2 Substitute $x$ with $-6$ in the second equation $y=-6-1$ $y=-7$ Solution: $(-6,-7)$ Check: $\left[\begin{array}{lll} -7\stackrel{?}{=}2(-6)+7 & ..... & -7\stackrel{?}{=}-6-1\\ -7=-13+7 & & -7=-7\\ -7=-7 & & \end{array}\right]$