What is the slope of the line?

Table which ratio is equivalent to 3: 7? 6: 7 3: 21 24: 56 15: 30

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

Asinusoidal function whose frequency is 1/6pi