I NEED TO PASS THIS COURSE

Which of the following expressions is a polynomial?

z2-1+z

z-2-1

5/y

7z-3+2

The parabola opens: y=√x-4 (principal square root) up down right left

The amount spent on food and drink by 20 customers is shown below what is the modal amount spent ?

Two airplanes start at the same place and travel in opposite directions,one at 395 miles per hour and the other at 422 miles per hour. how many hours will it take for the planes to be 2451 miles apart?