Question

Find n if n+2 Cn = 45​

Answer 1

Bhai mere ko nahi aa raha hai

Answer 2

Answer:

(n+2)!/{n!(n+2-n)!}=45.

(n+2)(n+1)n!/n!2!=45

(n+1) (n+2) =45×2! =90.

n^2+3n-88=0.

n^2+11n-8n-88=0

(n+11) (n-8)=0

n= -11,8.