What is 7x + 3 = 2x + 13

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

Answer for 10 points show work you guys in advanced < 3

If f(x)=x+7 and g(x)=1/x what is (fog)(x)