Question 892152
{{{(n+1)!=42(n-1)!}}}
{{{(n+1)n(n-1)!=42(n-1)!}}}
{{{(n+1)n=42}}}
{{{n^2+n-42=0}}}
{{{(n+7)(n-6)=0}}}
Two solutions but negative factorials are not defined.
{{{n-6=0}}}
{{{n=6}}}