Question

1) resolva o sistema
{x+y=7
{x- y = 3​

Answer 1

Resposta:

$\left \{ {{x+y=7} \atop {x-y=3}} \right.$

x = 7 - y

7 - y - y = 3

-2y = 3 - 7

-2y = -4 .(-1)

2y = 4

y = $\frac{4}{2}$ = 2

x = 7 - y

x = 7 - 2

x = 5