I didn’t see an image or anything but I looked it up and it said regular polygons, since they have the sides all the same length they must always be in the same proportions, and their interior angles are always the same.
(f-g)(x) = x²+6x - (7-x)
(f-g)(x) = x² + 6x - 7 + x
(f-g)(x) = x² + 7x - 7
(f-g)(9) = 9² + 7*9 - 7
(f-g)(9) = 81 + 63 - 7
(f-g)(9) = 137
-5 could not be used in the table again, because we have the value of x=-5 for the value of 15. Therefore correct option is C.
Answer: C. -5
