SOLUTION: Given that: 8( n+1Cn-1 ) = 5( nC1 )^2. Find the value of n

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Question 1136688: Given that: 8( n+1Cn-1 ) = 5( nC1 )^2. Find the value of n
Answer by greenestamps(13198) About Me  (Show Source):
You can put this solution on YOUR website!


(n+1)C(n-1) is the same as (n+1)C(2). Then the equation is 8*((n+1)C(2)) = 5*(nC1)^2

8%28%28n%2B1%29%28n%29%29%2F2+=+5%28n%29%5E2
8n%28n%2B1%29+=+10n%5E2
8n%5E2%2B8n+=+10n%5E2
2n%5E2-8n+=+0
2n%28n-4%29+=+0

ANSWER: n=4

CHECK:
8*5C3 = 8*5C2 = 8*10 = 80
5*(4C1)^2 = 5*16 = 80