Question

Sendo (x + y)

2 = 256 e x
2 + y
2 = 136, determine o valor de xy.

Answer 1

Resposta:

Explicação passo-a-passo:

$Temos\\\\(x+y)^{2}=256\\\\e\\\\x^{2}+y^{2}=136$

$Desenvolvendo\\\\(x+y)^{2}=256\\\\x^{2}+2xy+y^{2}=256\\\\Rearrumando$

$x^{2}+y^{2}+2xy=256\\\\136+2xy=256\\\\2xy=256-136\\\\2xy=120\\\\xy=\dfrac{120}{2}\\\\xy=60$