I'm having a difficulty in understanding the below questions:

(1) Use the natural number series to find the following

(a) The sum of the first n terms in the series (1)(3)(5) + (2)(4)(6) + (3)(5)(7) + ...

(b)

(c)

(2) Expand into partial fractions

(a) Use the above result to find

(b) Hence find the value of