Diketahui sistem persamaan 3x-5y =8 dan x+3y=11 nilai x+y adalah???

3x - 5y = 8
x + 3y = 11 |×3
maka
3x - 5y = 8
3x + 9y = 33
------------------(-)
- 14y = - 25
y = 25/14

3x - 5y = 8 |×3
x + 3y = 11 |×5
maka
9x - 15y = 24
5x + 15y = 55
--------------------(+)
14x = 79
x = 79/14

nilai x + y
= 79/14 + 25/14
= 104/14
= 7 6/14
= 7 3/7