Can anyone help me with this question

What is the axis of symmetry of the function f(x)=-(x+ 9)(x-21)

What else equals 42 and 30 for multiply

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