Question

resolva os sistemas
x+y=-1
3x-y=3

Answer 1

x+y= -1
3x +y= 3
 
x= -1 -y

3 (-1 -y) +y =3
-3 - 3y + y = 3
-3y + y = 3 + 3
-2y= 6 
2y= -6
y= -6/2
y= -3

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