Question

ALGUEM SABE A RESPOSTA ?2X-Y=3 SISTEMAS DE EQUAÇOES 1 GRAU
X+Y=3

Answer 1

$\begin{cases}2x-y=3\\ x+y=3\end{cases}\\\\\\\\ x+y=3\to~~x=-y+3\\\\\\\\ 2x-y=3\to~~ 2(-y+3)-y=3\to~~ -2y+6-y=3\to\\\\ -3y=3-6\to~~ -3y=-3\to~(-1)\to~~ 3y=3\to~~ y= \dfrac{3}{3} \to\\\\ \large\boxed{y=1} \\\\\\\\ x=-y+3\to~~ x=-1+3\to~~\large\boxed{x=2}\\\\\\\\\\ \Large\boxed{\boxed{S=\{ 2~;~1 \}}}$

Answer 2

2x - y = 3
x + y = 3

2x - 3 = y
y = 3  -x

2x - 3 = 3 - x
2x + x = 3 + 3
3x = 6
x = 6/3
x = 2

x + y = 3
2 + y = 3
y = 3 - 2
y = 1