ANSWER
[tex]x=0,y=-5[/tex]EXPLANATION
We want to solve the system of equations by subsitution:
[tex]\begin{gathered} y=-5 \\ 5x+4y=-20 \end{gathered}[/tex]To do this, substitute the first equation into the second:
[tex]\begin{gathered} 5x+4(-5)=-20 \\ 5x-20=-20 \\ \text{Collect like terms:} \\ 5x=-20+20 \\ 5x=0 \\ \text{Divide both sides by 5:} \\ x=0 \end{gathered}[/tex]Therefrore, the solution to the system of equations is:
[tex]x=0,y=-5[/tex]