$$\frac{ y }{ 6x-6y } - \frac{ x }{ 4x+4y } + \frac{ x(x-2y) }{ 3(x-y)(x-y) }$$
$\frac{\left(x-2y\right)\left(x^{2}+6xy+y^{2}\right)}{12\left(x+y\right)\left(x-y\right)^{2}}$
$\frac{x^{3}-11xy^{2}-2y^{3}+4yx^{2}}{12\left(x+y\right)\left(x-y\right)^{2}}$
