Sheridan Equipment Company sells computers for $1,660 each and also gives each customer a 2-year warranty that requires the company to perform periodic services and to replace defective parts. During 2020, the company sold 910 computers. Based on past experience, the company has estimated the total 2-year warranty costs as $40 for parts and $60 for labor. (Assume sales all occur at December 31, 2020.) In 2021, Sheridan incurred actual warranty costs relative to 2020 computer sales of $11,600 for parts and $17,400 for labor. (a) Under the expense warranty approach, give the entries to reflect the above transactions (accrual method) for 2020 and 2021. (Credit account titles are automatically indented when the amount is entered. Do not indent manually.)