Dgn cara substitusi himpunan penyelesaian dari sistem persamaan 3x+4y=17 5x+7y=29

3x + 4y = 17 ... (1)
5x + 7y = 29 ... (2) --> 5x = 29 - 7y
x = (29-7y) / 5
subtitusi x ke (1) -> 3x + 4y = 17
3 ((29-7y) /5) + 4y = 17 --> x 5
87 - 21y + 20y = 85
-y. = 85-87
-y. = -2
y. = 2
subtitusi y ke (1) -> 3x + 4(2) = 17
3x + 8. = 17
3x = 9
x = 3