dont know how to find the expression

Hi,

nCx =
10C6 = 10!/6!*4! = 10*9*8*7/4*3*2 = 30*7 = 210
12C8 = 12!/8!*4! = 495
14C10 = 14!/10!*4! = 14*13*12*11/4*3*2 = 7*13*11 = 1001