Question

estou querendo saber sobre x+2y=4 e x-y=1

Answer 1

{x+2y=4
{x-y=1
x=1+y
1+y+2y=4
1+3y=4
3y=4-1
3y=3
y=3/3
y=1
x+2y=4
x+2.1=4
x+2=4
x=4-2
x=2
S={(2, 1)}

Answer 2

x =1+ y

1+y +2y=4 → 3y =3 → y=1

x-1=1 → x= 2