Please help look at the picture and answer, help!

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∣∣

Can someone me out here and the tell me the greatest common factor

What unit of been sure would be appropriate for the volume of a sphere with a radius of 2 meters