4K⁴- 14K³ - 30K²

If you factor out the GCF of 2K², what's
left won't go up to the 4th power, but only to the 2nd power.

2K²(2K² - 7K - 15)

Then the trinomial in parentheses factors as this:

2K²(2K + 3)(K - 5)

Always look for a greatest common factor first.

Edwin