Question

resolva { x-2y=-5 { -2x+4y=10

Answer 1

x - 2y = 5. --> x = 5+2y
-2x+4y=10
-(5+2y)+4y=10
-5-2y+4y=10
-5+2y=10
2y=10-5
2y=5
y=5/2
x = 5+2y
x = 5+2*5/2
X = 5+10/2
X = 5+5
X = 10

S: {10, 5/2}

Answer 2

resolva

{ x-2y= -5---->(×2)
{-2x+4y=10

{x-2y= -5
{-2x+2y=5
-----------------(+)
-x=0
x=0