Question

Resolver sistema

A){×+y=-1
{3×-y=3

Answer 1

$\left \{ {{x+y=-1} \atop {3x-y=3}} \right. \\\\ somando\; as\; duas\; parcelas\\\\\\ 3x+x = 4x,\;y+(-y) = 0y,\;(-1)+3=2\\\\ 4x = 2 \Rightarrow x = \frac{2}{4} = \frac{1}{2} \\\\\\ substituindo\; na\;primeira\;equa\c{c}\~{a}o\\\\\\ \frac{1}{2} +y = -1 \Rightarrow y = -1 - \frac{1}{2} = \frac{-2-1}{2} = -\frac{3}{2} \\\\\\ Solu\c{c}\~{a}o:\;\; \framebox{ x = \dfrac{1}{2} \;\;e\;\;y= -\dfrac{3}{2} }$