x + y = 28 x - y = 12

x+y = 28
x-y = 12

pake eliminasi eduanya di tambah jadi

x+y = 28
x-y = 12   +
2x  = 40
x = 40/2
x = 20

terus masukin 
x+y = 28
20 + y = 28
y = 28-20
y = 8
 

jawabannya
x =20
y= 8