Answer:
the ans has to be 6.........
126
Step-by-step explanation:
n! / (r! (n-r)!)
In this case n = 9 and r = 4
9!/ (4! * (9-4)!)
9!/ (4! * 5!)
= 126
9! = 9x8x7x6x5x4x3x2x1
See below
(36 - 2x) * (17-2x) = 700 I think, given the info
4x^2 - 106x + 612 = 700 expanded....
2