SOLUTION: CAN SOMEONE HELP PLEASE.... 2 x nP2 + 50= 2nP2 is? a. 3 b. 4 c. 5 d. 6 I cannot figure this one out

Question 181304: CAN SOMEONE HELP PLEASE....
2 x nP2 + 50= 2nP2 is?
a. 3
b. 4
c. 5
d. 6
I cannot figure this one out
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
2 x nP2 + 50= 2nP2 is?
2[(n)!/(n-2)!] + 50 = [(2n)!/(2n-2)!]
2[n(n-1)(n-2)!/(n-2)!] + 50 = [(2n)(2n-1)(2n-2)!/(2n-2)!]
----------------------------
2[n(n-1)] + 50 = (2n)(2n-1)
n(n-1) + 25 = n(2n-1)
n^2 - n + 25 = 2n^2 - n
n^2 = 25
n = 5
-----------------
Cheers,
Stan H.
====================

a. 3
b. 4
c. 5
d. 6

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