Help plz asap! test due today​

If the sales price of a dvd is $20 and the markup is 34%, what is the cost of the dvd?

If private savings 'v' = 0.75s and total savings 's' equals $4.20 billion, solve for public and private savings.

In order for the function to be linear, what must m be and why? m = 22 because the rate of change is 1. m = 20 because the rate of change is 3. m = 22 because the rate of change is -1. m = 20 because the rate of change is -3.