Question

qual e a resposta?
x+y=5
4x-y=0

Answer 1

{x+y=5
{4x-y=0
5x=5
x=5/5
x=1
4x-y=0
4.1-y=0
4-y=0
-y=0-4
-y=-4.(-1)
y=4
S={(1, 4)}