Question

os pares ordenados reais (x+y;8) e (10; x-y) são iguais. Calcule x.y

Answer 1

x+y=10
x-y=8

x+y=10
x-y=8
______
2x=18
x=18/2
x=9

x+y=10
9+y=10
y=10-9
y=1