Kak tolong ini gimana pakai caranya ya kak;).

(x/3) + (y/5) = 3
---------------------- ×15
5x + 3y = 45

(x/3) - (y/5) = -1
kali 15
5x - 3y = -15


5x + 3y = 45
5x - 3y = -15
--------------------- +
10x = 30
x = 3

5x + 3y = 45
5(3) + 3y = 45
15 + 3y = 45
3y = 30
y = 10

x + y =3+10 = 13 (d)