50 points dropped, i need help wit sumthing...

Alake near the arctic circle is covered by a sheet of ice during the cold winter months. when spring arrives, the ice starts to melt. s(t) models the ice sheet's thickness (in meters) as a function of time tt (in weeks). s(t)=-0.25t+4

What is the definition of exponential decay?

Ben is three times as old as samantha, who is two years older than half of michel's age. if michel is 12. how old is ben?