The easiest way for me to factor things is to first pull out everything that is in common. In your first factoring problem you have a 2 and an x and a y in both terms, so you can pull out a 2xy.
2(x^5)y - 32xy --> 2xy*(x^4-16) Once that's done we can look for any tricks for factoring that we've learned. This one has a difference of squares in parentheses, which we know we can factor using the square roots of the terms
The rest can be solved similarly.