Craig Mallery's Band Wants to Record a CD $\$ 750$ For Studio Fees Plus

Craig Mallery's band wants to record a CD. The cost to record a CD is $\$ 750$ for studio fees plus $\$ 4.50$ for each CD produced.
(a) Write a cost function $C$ , where $x$ represents the number of CDs produced.
(b) Find the revenue function $R$ , if each $\mathrm{CD}$ in part (a) sells for $\$ 12.00$ .
(c) Give the profit function $P$ .
(d) How many CDs must be produced and sold before the band earns a profit?
(e) Support the results of part (d) graphically.