Question 1026784
The revenue equation in this case would be 

R(n) = n(720-10n),

which is a a quadratic equation with roots at n = 0, 72. (n = 0 means no production, hence 0 revenue. n = 72 means 0 sales because the price is highest at $72.)

The $ price that would yield the maximum revenue would be midway between $0 and $72, which is $36.  This would give a max revenue of $12,960.