ii) Find n, if (n + 1)! = 42 x (n - 1)!
Answers
Answered by
0
Answer:
n= 6 or -7
Step-by-step explanation:
(n+1)!= 42*(n-1)!
=> (n)(n+1)(n-1)!= 42*(n-1)!
Cancel (n-1)! from both sides.
=> (n)(n+1)= 42
=> n²+n-42=0
=> (n-6)(n+7)=0
=> n= 6 or n= -7
Answered by
0
Step-by-step explanation:
(n+1)! =42×(n-1)!
(n+1)! /(n-1)! =42
n(n+1) =42
n^2+n-42=0
n^2+7n-6n-42=0
n(n+7)-6(n+7)=0
(n+7)(n-6)= 0
n= -7 (not possible) or n= 6(answer)
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