Question

1- Resolva pelo método da adição os sistemas, Sendo U = IR x IR: A) x + y = 6 x - y = 4 B) x + 2 y = 5 3x - 2y = -17​

Answer 1

$\Large\boxed{\begin{array}{l}\tt A)\\+\underline{\begin{cases}\sf x+\backslash\!\!\!y=6\\\sf x-\backslash\!\!\!y=4\end{cases}}\\\sf2x=10\\\sf x=\dfrac{10}{2}\\\\\sf x=5\\\sf x+y=6\\\sf 5+y=6\\\sf y=6-5\\\sf y=1\\\sf S=\{5,1\} \end{array}}$

$\Large\boxed{\begin{array}{l}\tt B)\\+\underline{\begin{cases}\sf x+\diagdown\!\!\!\!\!\!2y=5\\\sf 3x-\diagdown\!\!\!\!\!\!2y=-17\end{cases}}\\\sf 4x=-12\\\sf x=-\dfrac{12}{4}\\\\\sf x=-3\\\sf x+2y=5\\\sf -3+2y=5\\\sf 2y=5+3\\\sf 2y=8\\\sf y=\dfrac{8}{2}\\\\\sf y=4\\\sf S=\{-3,4\}\end{array}}$