bantuin caranya nmr 3&4 dong..

jawab

6c3 =  6.5.4 / 3 x 2 =  5 x4  - 20

10c3 = 10.9.8. /3 x 2 =  120

12 c7 = 12 .11. 10 / 3 x  2 =  220

4. banyak cara   =-8C5 x (8-5)C3 = 8c5 x 3 c3 = 56 (1)=  56