Find the formula of

Question

n
Σ (j+3)(j-4)
j=1

I have gotten to
n(n+1)(2n+1)/6 - n(n+1)/2 - 12n
How do I simplify it from there?

Answer 1

see your other post. Repeating it does no one any good.

Don't forget your Algebra I now that you're taking Calculus!