Answer :
Eliminate the y by making them zero.
-9x=-20
5x=4
Combine
-4x=-16
Divide each side by 4 to put the x alone
-4x/4= -16/-4
X=4
Plug x=4 back into one of the equations. It does not matter
5(4)+4y=4
20+4y=4
-20 -20
4y=-16
Divide by 4
Y=-4
-9x=-20
5x=4
Combine
-4x=-16
Divide each side by 4 to put the x alone
-4x/4= -16/-4
X=4
Plug x=4 back into one of the equations. It does not matter
5(4)+4y=4
20+4y=4
-20 -20
4y=-16
Divide by 4
Y=-4