Find n if (n+1)!= 42(n-1)!
Answers
Answered by
6
Answer:
n = 6
or
n = -7
Step-by-step explanation:
(n+1)! = 42(n-1)!
=> (n+1) (n) (n-1)! = 42 (n-1)!
=> (n+1)(n) = 42
=> n² + n - 42 = 0
=> n² + (7-6)n - 42 = 0 .......{ splitting middle term}
=> n² + 7n - 6n - 42 = 0
=> n(n+7) - 6(n+7) = 0
=> (n+7)(n-6) = 0
either. (n+7) = 0 .........or.......... (n-6) = 0
either n = (-7) .............or........ n = 6
therefore
n = 6
or
n = -7
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