Can somebody explain how to do this

Two lines parallel to the same plane are parallel to eachother

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

The relative growth rate for a certain type of fungi is 60% per hour.a small culture has formed and in just 6 hours the count shows to be 20,273 fungi in the culture.what is the initial number of fungi in the culture?