Question

$\left \{ {{x+y=36} \atop {4x+2y=112}} \right.$

Answer 1

Oi 

x + y = 36 
2x + y = 56

2x - x = 56 - 36
x = 20

20 + y = 36
y = 36 - 20 = 16 

S = (20, 16)