You can
put this solution on YOUR website! .
It is from 3 to 5 minutes work for the person who has Excel in his/(or her) computer.
Alternatively, I can re-write the sum in this form
2 + 4(3)^2 + . . . + 22(21)^2 =
= 1 + 3^3 + . . . + 21^3 +
+ 1 + 3^2 + . . . + 21^2
and then refer you to my lesson
- Mathematical induction for sequences other than arithmetic or geometric, Problem 1 and Problem 2
in this site, where you will find the way on how to proceed further.
Since your problem is above the average school Math, I assume that your level corresponds to the problem's level,
and you will be able to complete it on your own.
Good luck and happy learning ! !
