Question

Determine o valor do sistema de equação abaixo: *
Imagem sem legenda
a) x = 4 e y= 2
b) x = 2 e y = 1
c) x = 1 e y = -1
d) x = -1 e y = 1
e) x = -2 e y = -1​

Answer 1

$\large\boxed{\begin{array}{l}\begin{cases}\sf2x+y=-1\\\sf x+2y=1\end{cases}\\\\+\underline{\begin{cases}\sf-4x-2y=2\\\sf x+2y=1\end{cases}}\\\sf-3x=3\cdot(-1)\\\sf 3x=-3\\\sf x=-\dfrac{3}{3}\\\sf x=-1\\\sf2x+y=-1\\\sf2\cdot(-1)+y=-1\\\sf -2+y=-1\\\sf y=2-1\\\sf y=1\\\sf S=\{(-1,1)\}\\\huge\boxed{\boxed{\boxed{\boxed{\sf\maltese~alternativa~d}}}}\end{array}}$