whe can replace the second equation on the first equation to find x
[tex]\begin{gathered} 12x-5(x+4)=-20 \\ 12x-5x-20=-20 \\ 7x=-20+20 \\ x=\frac{0}{7} \\ \\ x=0 \end{gathered}[/tex]the value of x is 0, now i can replace x=0 on any equation and find y
i will replace x=0 on the second equation
[tex]\begin{gathered} y=(0)+4 \\ y=4 \end{gathered}[/tex]the value of y is 4