Tính
a) (\(\frac{1}{3}x\) + 2y)(\(\frac{1}{9}x^{2^{ }}\)- \(\frac{2}{9}xy\) + 4y2)
b) (x2 - \(\frac{1}{3}\) )(x4 + \(\frac{1}{3}x^2\) + \(\frac{1}{9}\))
c) (x2 - 3y2 )(9y4 + x4 + 3x2y2)
d) (x3 + 2y3)(-2x3y3 + x6 + 4y6)
e) (-2x2 - 3y)(4x2 + 9y2 - 6x2y)