Question

Se ×+2y=8
2×+y=6
Então o Valor De ×y é?

Answer 1

Resolvendo o sistema:

x+2y=8 -> x = 8-2y
2x+y=6 -> x = (6-y)/2

(6-y)/2 = 8-2y -> 6-y = 16-4y -> -y = 16-4y-6 -> -y = 10-4y ->
-> -y + 4y = 10 -> 3y = 10    ->    y=10/3

Se y = 10/3 e X = 8 - 2y, logo X = 8-2*(10/3)
X = 8-(20/3)  -> X = (24 - 20)/3  -> X = 4/3

Temos que Y = 10/3 e X = 4/3 logo, X*Y = 10/3 * 4/3 = 40/9 

Resposta: X*Y = 40/9