subtisikan bilangan 4x + 2y =8 2x + 4y = 8

4x + 2y = 8 => 2y = 8 - 4x | : 2 | => y = 4 - 2x

2x + 4y           = 8
2x + 4(4 - 2x) = 8
2x +16 - 8x     = 8
16 - 6x            = 8

4x+2y=8
2x+4y=8

subtitusi 4x+2y=8(8-4y=2x⇔4-y=x),kepersamaan pertama:
4(4-y)+2y=8
16-4y+2y=8
-4y+2y=8-16

mohon ma'af apabila salah