y= -2x-7 y= -3x-9 Solving systems of equations using substitution

[latex]y=-2x-7 \\ y=-3x-9 \\ \\ \hbox{substitute -2x-7 for y in the 2nd equation:} \\ -2x-7=-3x-9 \\ -2x+3x=-9+7 \\ x=-2 \\ \\ y=-2x-7=-2 \times (-2)-7=4-7=-3 \\ \\ (x,y)=(-2,-3)[/latex]