Exercício sobre álgebra elementar

(PUC) Simplificada a expressão $\phantom{X}\dfrac{\;x^3\,-\,3x^2y^2\,+\,2xy^3\;}{x^4y\,-\,8xy^4}\phantom{X}$ temos:

$\,\dfrac{x\,-\,y}{\;x^2\,+\,2xy\,+\,4y^2\;}\,$

$\,\dfrac{x\,+\,y}{\;x\,-\,y\;}\,$

$\,\dfrac{x(x\,-\,y)}{\;x(x\,+\,y)\;}\,$

$\,\dfrac{x\,-\,y}{\;(x\,-\,2y)^2\;}\,$

$\,\dfrac{x\,+\,2y}{\;x^2\,-\,2x\,+\,4y^2\;}\,$

resposta: (A)
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