Question

x+y = 3 e x . y =0 resolva mentalmente

Answer 1

x + y = 3
x = 3 - y

x.y = 0
(3 - y).y = 0
y = 0

3 - y = 0
3 = y
y = 3

y = 0
x = 3 - y
x = 3 - 0
x = 3

y = 3
x = 3 - y
x = 3 - 3
x = 0

R.: Um deve ser 0 e o outro 3. Se x = 0; y = 3. Se x = 3; y = 0.