Question

Resolva os seguintes sistemas:

x-y=3
2x+y=9

Answer 1

x-y=3
2x+y=9

x=3+y
2(3+y) +y =9

6+2y +y =9
3y=9-3
3y=6
y=6/3
y=2

x=3+ y
x=3+2
x=5

S={(5,2)}