I have a small comprehension gap with an easy equation. I have following term and I don’t know how to multiply it correctly. $ (n+1)(n+1)!+(n+1)!-1 $
One intermediate step must be. $ (n+2)(n+1)!-1 $
The result should be $ (n+2)!-1 $.
How do I multiply the term correct? Is the attempt correct to multiply binomial series to $ (n+1)^2n!+(n+1)!-1 $?
It would awesome, if someone could help me.