1) \(\boxed{xy^5 \sqrt[3]xy}\). You can change the expression directly to \(x^{2\cdot \dfrac{2}{3}}y^{8\cdot \dfrac{2}{3}}\).

2) I am not 100% sure about this.

3) \(\boxed{\dfrac{x^2-x-6}{2x+3}}\) . Just factor out x^2-9, x^2-3x-10, and 2x^2 - 7x - 15.

= (x^4−3x^3−19x^2+27x+90) / 2x^3−x^2−36x−45

= (x+2)(x+3)(x−3)(x−5) / (x+3)(2x+3)(x−5)

= (x^2−x−6) / (2x+3)

- PM