Amortization Expense

For each of the following unrelated situations, calculate the annual amortization expense and prepare a journal entry to record the expense:

a$.$ A patent with a $15-$year remaining legal life was purchased for $$616,000.$ The patent will be commercially exploitable for another seven years.

b$.$ A patent was acquired on a device designed by a production worker. Although the cost of the patent to date consisted of $$93,780$ in legal fees for handling the patent application, the patent should be commercially valuable during its entire remaining legal life of $18$ years and is currently worth $$720,000.$

c$.$ A franchise granting exclusive distribution rights for a new wind turbine within a three$-$state area for four years was obtained at a cost of $$66,400.$ Satisfactory sales performance over the four years permits renewal of the franchise for another four years $($at an additional cost determined at renewal$).$

$\backslash$table$[[$Ref$.,$General Journal,Credit$],[$Description$,,$Debit$],[$a$.,,*{*}^{},0,0],[,-{?}^{},0,0],[$To record patent amortization.,,,$],[$b$.,3,,0,0],[(2),$hat$(),0,0],[$To record patent amortization.,,,$6],[$c$.,,$hat$(),0,0],[43,$hat$(),0,0],[$To record franchise amortization.,,,$]]$

Please answer all parts of the question.