Answer:
(2x + 3)(x - 7)
Step-by-step explanation:
I believe the term is a "radical"
Hope this helps!
I think with the kinds of mixture problems, it's really helpful to make a table.
The equations you actually need are

and

. Since I was so close, I went ahead and just solved it anyway. You can see my setup on the attached image.
True every diameter of a circle is a chord.
hope it helps