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If (n+3)! =56[(n+1)! fin n...

If `(n+3)! =56[(n+1)! ` fin n

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Given,`((n+3)!)=56[(n−1)!]`
=`((n+3)×(n+2)×(n+1)!) = 56[(n+1)!]`
=`(n+2)(n+3)=56`
=`n^2+3n+2n+6=56`
=`n^2+5n+6−56=0`
=`n^2+5n−50=0`
=`n^2+10n−5n−50=0`
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RD SHARMA-PERMUTATIONS-Solved Examples And Exercises
  1. if(n+2)! =60[(n-1)!],find n

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  2. If (n+1)! =90[(n-1)!], fin d n

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