subtitusi dari 4x - 3y - 8 = -19 dan 2x + y + 9 = 16

4x-3y-8=-19
4x-3y=-19+8
4x-3y=-11
x=-11+3y/4
substitusi x ke pers
2x+y+9=16
2 (-11+3y/4)+y+9=16
-22/4+6y/4+y+9=16
6y/4+y=16-9+22/4
6y/4+4y/4=64/4-36/4+22/4
10y/4=50/4
4×10y=50×4
40y=200
y=200/40
y=5