Question

03. Determine o conjunto solução do sistema abaixo: *

x + 2y = 4
1 x+y=3

a) S = {2, 1}

O b) S = (-2, -1}

c) S = {-1,2}

d) S= (-2, 2} ​

Answer 1

$\begin{matrix} \underbrace{~~M\acute{e}todo~~da~~substituic_{\!\!,} \tilde{a}o~~}\\\\\\ x~+~y~~=~~3~~~\iff~~~x~=~3~-~y\\\\\\ x~+~2y~~=~~4\\\\ (3~-~y)~+~2y~~=~~4\\\\ 3~-~y~+2y~~=~~4\\\\ 3~+~y~~=~~4\\\\ y~~=~~4~-~3\\\\ \boxed{~y~~=~~1~}\\\\\\\\ x~+~y~~=~~3\\\\ x~+~1~~=~~3\\\\ x~~=~~3~-~1\\\\ \boxed{~x~~=~~2~} \end{matrix}$

$\mathbb{ \bf RESPOSTA:} \\\\ A) \ \ S \ = \ \{ \ 2, \ 1 \ \}$