Which function are not linear ?

You and a friend race across a field to a fence and back. your friend has a 50-meter head start. the equations shown represent you and your friend's distances dd (in meters) from the fence tt seconds after the race begins. find the time at which you catch up to your friend. you: d=∣−5t+100∣d=∣−5t+100∣ your friend: d=∣−313t+50∣∣

:24% of students in a class are girls. if there are less than 30 students in this class, how many students are there? how many girls are there?

Write an inequality for this description. - one fourth of the opposite of the difference of five and a number is less than twenty.