Please help solve this combination
Algebraically solve nC7 = n+1C8?
- Posted:
- 3+ months ago by Cfox
- Topics:
- math, mathematics, help
Details:
Answers (1)
nC7 = n! / 7!(n-7)!
n+1C8 = (n+1)! / 8!(n+1-8)!
nC7 = n+1C8
Rearranging gives:
nC7 - n+1C8 = 0
Rewrite in factorial form
n! / 7!(n-7)! - (n+1)! / 8!(n+1-8)! = 0
Rewrite 8! in the denominator
n! / 7!(n-7)! - (n+1)! / 7!*8(n-7)! = 0
Rewrite with common denominator
n!*8 / 7!*8(n-7)! - (n+1)! / 7!*8(n-7)! = 0
Divide by n! / 7!*8(n-7)!
8 - (n+1) = 0
8 - n - 1 = 0
7 - n = 0
n = 7