jika 4x + 5y = 30 dan yx + 8y = 40 tentukan nilai 3x-29

Eliminasi :
4x + 5y = 30 |×8|
yx + 8y = 40 |×5|
_____________
32x + 40y = 240
5yx + 40y = 200
____________ _
32x - 5yx = 40
yx - 32x = 40/5
yx - 32x = 8
yx - x = 8/32
y = 8/32
y = 1/4

Substitusi :
yx + 8y = 40
(1/4)x + 8(1/4) = 40
1/4x + 2 = 40
1/4x = 40 - 2
1/4x = 38
x = 38 x 4
x = 152

Dit :
3x - 29
3(152) - 29
456 - 29 = 427