Question

Find n if (n+1)!= 42(n-1)!​

Answer 1

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