I need help with this workshop is about Polynomial factorixation

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

Write the percent as a fraction or mixed number in simplest form. 0.8%

Which shows one way to determine the facts of x3+4x2+5x+20 by grouping