Question

(1)
Find the value of "n" or "r":
nCn-2 = 28
​

Answer 1

Answer:

ramramramramramteramramramramramramramramramram

Answer 2

Answer:

n!/(n-2)!2! = 28

n(n-1)(n-2)! /(n-2)! = 56

n(n-1) = 56

n2-n-56= 0

n2-8n+7n-56=0

n(n-8)+7(n-8) = 0

(n+7)(n-8) = 0

n = 7. r = 5

n = 8. r = 6