Precalculus, Chapter 9, 9.5, Section 9.5, Problem 10

Use the formula _nC_r=(n!)/(r!(n-r)!)
_12C_5=(12!)/(5!(12-5)!)
=(12*11*10*9*8*7!)/(5*4*3*2*1*7!)
=(12*11*10*9*8)/(5*4*3*2*1)
=792