Vamos là.
sistema
(x + y)/2 = 7
2y - x = 10
x + y = 14
-x + 2y = 10
adição
3y = 24
y = 8
x + 8 = 14
x = 6
S = (6, 8)
[tex]x + y = \frac{7}{2} \\ \underline{ - x + 2y = 10 } \\ 0 + 3y = \frac{27}{2} \implies y = \frac{9}{2} \\ \\ \\ x + \frac{9}{2} = \frac{7}{2} \implies x = \frac{7}{2} - \frac{9}{2} = - 1[/tex]
