Question

caucule o sistema:
x+y=3
x-y=1

Answer 1

x+y =3
x = 3 - y

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

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