Question

{x-y=6
{x+y= -7 qual o resultado???

Answer 1

$RESUMINHO..\\\\\begin{bmatrix}x-y=6\\ x+y=-7\end{bmatrix}\\\\\begin{bmatrix}6+y+y=-7\end{bmatrix}\\\\\mathrm{Para\:}x=6+y\\\\\mathrm{Substituir\:}y=-\frac{13}{2}\\\\x=6-\frac{13}{2}\\\\x=-\frac{1}{2}\\\\x=-\frac{1}{2},\:y=-\frac{13}{2}$

Answer 2

$\large\boxed{\begin{array}{l}+\underline{\begin{cases}\sf x-\backslash\!\!\!y=6\\\sf x+\backslash\!\!\!y=-7\end{cases}}\\\sf 2x=-1\\\sf x=-\dfrac{1}{2}\\\sf x+y=-7\\\sf-\dfrac{1}{2}+y=-7\cdot(2)\\\sf -1+2y=-14\\\sf 2y=1-14\\\sf 2y=-13\\\sf y=-\dfrac{13}{2}\\\sf S=\bigg\{\bigg(-\dfrac{1}{2},-\dfrac{13}{2}\bigg)\bigg\}\end{array}}$