Sistem persamaan dua variabel 3x+y =15 x-y =4

3x+y=15
x-y=4
agar bisa dieliminasi, ruas dikalikan 3

3x+y=15
3x-3y=12
dikurangiii

4y=3
y=3/4

x-y=4
x- 3/4 = 4
x = 4+ 3/4
x = 19/4