Question

como resolvo 3x+y=11 / x-y=-3

Answer 1

3.x + y = 11       x - y = -3
3.2 + 5 = 11       ↓   ↓ 
 ↓
 6   + 5 = 11       2 - 5 = -3 

Answer 2

x=5-y 3(5-y)-y=11 15-3y-y=11 -4y=-4 y=1 x=5-1=4