We recognise this is a product `y=uv`, where

`u=(x^3-6x)` and `v=(2-4x^3)`

So we have:

`(d(uv))/(dx)=u(dv)/(dx)+v(du)/(dx)`

`=(x^3-6x)(-12x^2)+` `(2-4x^3)(3x^2-6)`

`=-12x^5+72x^3+6x^2-` `12-` `12x^5+` `24x^3`

`=-24x^5+96x^3+6x^2-12`

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