A baseball bat cost $28. There is a 25% discount. How much will you pay after the discount?

The variable z is directly proportional to x, and inversely proportional to y. when x is 4 and y is 13, z has the value 1.2307692307692. what is the value of z when x= 9, and y= 20

How do i make someone brainliest? (if you answer me, i might be able to make you brainliest! )

Can someone tell me if this is perpendicular? !