Question

Resolva:
{x+y=2
{3x+2y=9

Answer 1

$\left \{ {x+y=2} \atop {3x+2y= 9}} \right.$

Isolar x:
x = 2 - y
Substituindo:
3x+2y= 9
3.(2 - y) +2y=9
6 - 3y +2y= 9
-3y+2y = 9 - 6
y= -3  

Substituindo o y
3x+2y=9
3x+ 2 .(-3) = 9
3x= 9 +6
x=15/3
x=5

Logo: x=5  e y=-3

Answer 2

{x+y=2 (-2)
{3x+2y=9

{-2x-2y=-4
{3x+2y=9

x=5

3(5)+2y=9
15+2y=9
2y=9-15
y=-6/2
y=-3