Solve by substitution
[tex]\sf{y=-x-1}[/tex]
[tex]\sf{y+x=3}[/tex]
Just plug in y=-x-1 into y+x=3
So we get:
[tex]\sf{(-x-1)+x=3}[/tex]
Simplify that:
[tex]\sf{-1=3}[/tex]
And since that is not true, that means this system of equations has no solutions!
