-7 + ? = 12

A) -19

B) -5

C) 5

D) 19

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

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?

Me because i don't understand how to do it.: )