Use f(x) =1/2 x and f^-1(x)=2x to solve the problems f(2)= f^-1(1)= f^-1(f(2))=

David and alton are training for a race. they spend 35 minutes stretching and then go on a 5 mile practice run. david runs at a pace of 7 min/mile. alton runs at a pace of 8 min/mile. write an equation for each runner that shows the total length of their workout. then solve each equation showing your work