Question

calcule: a)C6,2 b)C9,5 c)C15,10

Answer 1

6/(6-2) = ( 6! / 4! ) = 6 * 5 * 4 )/4 = 6 * 5 = 30
9/( 9-5) = ( 9! / 4! ) = 9* 8 * 7 * 6 * 5 * 4) / ( 4 ) =  9*8*7*6*5 = 15120
15( 15 -10) = ( 15! / 5!  ) = 15*14*13*12*11*10*9*8*7*6*5) / 5 = 15*14*13*12*11*10*9*8*7*6*5* =