penyelesaian sistem persamaan 3×+2y=17 dan 4×-y=8 maka nilai ×+y adalah..

3x + 2y = 17 ...(1)
4x - y = 8
y = 4x -8...(2)

subtitusi
3x +2y = 17
3x +2(4x -8) =17
3x +8x -16 = 17
11x = 33
x = 3

y = 4(3) -8
y = 4

jadi nilai x + y = 3+4 = 7

3x + 2y = 17 |×4
4x - y = 8 |×3

12x + 8y = 68
12x - 3y = 24
___________ -
11y = 44
y = 4

12x + 8y = 68
12x + 32 = 68
12x = 36
x = 3

nilai x - y = 3 + 4 = 7