1a) Let f(x)=ax^2-4x-c. A horizontal line, L, intersects the graph of f at x= -1 and x=3 The equation of the axis of symmetry is x=p. Find p

1b) Hence, show that a=2

1c) The equation of L is y=5. Find the value of C.

Ben frank is an electrician who installs lighting fixtures. he charges (in dollars) his clients 15h+40f15h+40f where hh is the number of hours worked and ff is the number of fixtures installed. how much does ben frank charge when he works 77 hours and installs 99 fixtures?