Question

$(x + y = 5 \\ (x - y = 9$
determine a solução dos sistemas ​

Answer 1

$\boxed{\begin{array}{l}+\underline{\begin{cases}\sf x+\backslash\!\!\!y=5\\\sf x-\backslash\!\!\!y=9\end{cases}}\\\sf 2x=14\\\sf x=\dfrac{14}{2}\\\sf x=7\\\sf x+y=5\\\sf 7+y=5\\\sf y=5-7\\\sf y=-2\\\sf S=\{7,-2\}\end{array}}$

Answer 2

Explicação passo-a-passo:

{x+y=5

{x-y=9

2x=14

x=14/2

x=>7

x+y=5

7+y=5

y=5-7

y=>-2