Jika 9 . nP2 = 3. (n+1)P2 Maka n =..........

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9.nP2 = 3.(n+1)P2
9.( n!)/(n= 2) = 3.(n+ 1)!/{(n + 1: ) - 2}!
9.{ n (n-1)(n-3)!/(n-2) = 3 {(n'1)(n)(n-1)!/(n-1)!
=3.n (n-1 ) = (n +1 ) n
= 3n^2 -4n = n^2 + n
= 2n^2 - 4n =0
2n ( n- 2 ) =0
n = 0 atau n= 2. jadi n = 2 karena n€A