Mr. Zakowski's physics class is building a radio. So far, the class has learned that the frequency of a radio wave varies directly as the length of the radio wave. A 750 meter radio wave has a frequency wave of 400 kilohertz. What is the frequency of a radio wave that is 300 meters long?

Any is very appreciated! (picture is provided below)not sure how to do this at all won't lie

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

What number is 7 units left of -15?