We can substitute the second equation in the first one
[tex]\begin{gathered} 12x-5(x+4)=-20 \\ 12x-5x-20=-20 \\ 7x=0 \\ x=0 \end{gathered}[/tex]Since x=0, then
[tex]\begin{gathered} y=0+4 \\ y=4 \end{gathered}[/tex]to be sure, we replace the result in the first equation
[tex]12(0)-5(4)=0-20=-20[/tex]Then the answer is x=0, y=4
