2x + 3y = 3 dan 5y + 9x =19 tentukan nilai 2x-y

2x + 3y = 3 | x9|
9x + 5y =19 | x2|
menjadi
18x + 27y = 27
18x + 10 y = 38
———————— -
17y = - 11
y = -11/17

2x + 3y = 3
2x + 3(-11/17) =3
2x -33/17 =3
2x = 3+33/17
2x = 84/17

sehingga 2x - y = 84/17-(-11/17)
= 95/17