Given sin y = -4/5, where π < y < 3π/2, and cos x = 12/13, where 0 < x < π/2. Find the exact value of sin (x - y). Please show all the exact steps in order I am really lost on how to solve this.

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