Use summation notation to write the series for five terms

Which shows one way to determine the factors of 4x3 + x2 – 8x – 2 by grouping?

I'm confused on this could anyone me and show me what i need to do to solve it.

Suppose you are an avid reader and are looking to save money on the cost of books instead of paying about $20 for each book, you decide to look into purchasing a kindle for $120 you can purchase e-books for about $5 each 1. find the slope-intercept equation for the cost of the hard copy of books using x to represent the number of books 2. find the slope-intercept equation for the cost of the kindle with cost of e-books using x to represent the number of books