[tex]\begin{gathered} y=-x+4 \\ \text{Multiply both sides by 2:} \\ 2\cdot y=2(-x+4) \\ 2y=-2x+8 \end{gathered}[/tex][tex]\begin{gathered} y=2x+6\text{ (1)} \\ y=2x-1\text{ (2)} \\ (1)-(2) \\ 0=7 \end{gathered}[/tex][tex]\begin{gathered} y=-3x+6\text{ (1)} \\ y=x+2\text{ (2)} \\ (1)-(2) \\ 0=-4x+4 \\ x=1 \\ y=3 \end{gathered}[/tex]
