a) ( \(18x^6y-4x^3y^5+4x^2y^6\) ) : \(6x^2y\)
= ( \(18x^6y:6x^2y\) ) + (\(-4^3y^5:6x^2y\) ) + (\(4x^2y^6:6x^2y\) )
= \(3x^3y-\dfrac{2}{3}xy^5+\dfrac{2}{3}y^5\)
b)( \(x^3-3x^2y+3xy^2-y^3\) ) : \(\left(y-x\right)^2\)
= \(\left(x-y\right)^3\) : \(\left(y-x\right)^2\)
= \(\left(x-y\right)^3:-\left(x-y\right)^2\)
=\(-\left(x-y\right)\)