Question

5 x - 3y =a
4X + 2Y = 16

Answer 1

2x-y=3 → 2.(5-3y) - y = 3 → 10 - 6y - y = 3 → -7y = 3 - 10 → -7y = -7 → y = -7/-7 → y = 1 

Retome 
x = 5 - 3y 
x = 5 - 3.1 
x = 5 - 3 
x = 2 

S = (2, 1)