Hello there!
Simply find a common term that they all have!
So they can all be divided by 6, right? So let's take a 6 out.
6 (x^2-8x-20)
Now factor the terms in the parenthesis!
6 (x-10) (x-2)
^ This is NOT your answer!!
Tip: When looking at (x^2-8x-20), look at the middle term. (-8x). Since it's negative, either (x-10) or (x-2) can be negative.
Which one is negative? Well, is the 8 positive or negative? Since the 8 is negative, the parenthesis bigger number (x-10) will be negative!
So it'll be:
6 (x-10) (x+2)
ALWAYS double check your answer by foiling! :)
Hope this helped!
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DISCLAIMER: I am not a professional tutor or have any professional background in your subject. Please do not copy my work down, as that will only make things harder for you in the long run. Take the time to really understand this, and it'll make future problems easier. I am human, and may make mistakes, despite my best efforts. Again, I possess no professional background in your subject, so anything you do with my help will be your responsibility. Thank you for reading this, and have a wonderful day/night!