During 2013, Sheffield Corporation spent $165,600 in research and development costs. As a result, a new product called the New Age Piano was patented. The patent was obtained on October 1, 2013, and had a legal life of 20 years and a useful life of 10 years. Legal costs of $41,040 related to the patent were incurred as of October 1, 2013.

I figured out the first part (above) but am stuck on the bottom part and it's journal entries. If you can show work too it would really help me out! Thank you!

On June 1, 2015, Sheffield spent $30,240 to successfully prosecute a patent infringement suit. As a result, the estimate of useful life was extended to 12 years from June 1, 2015. Prepare all journal entries required in 2015 and 2016. (Round answers to O decimal places, e.g. 8,564. Credit account titles are automatically indented when amount is entered. Do not indent manually. If no entry is required, select "No Entry" for the account titles and enter 0 for the amounts.) Date Account Titles and Explanation Debit Credit 2015 Patents 30240 cash 30240 (To record patents) 2015 n Expense 2966 Patents 2966 To record amortization expense) 2016 n Expense 2273 Patents 2273 SHOW LIST OF ACCOUNTS Your answer is incorrect. Try again. In 2017, Sheffield determined that a competitor's product would make the New Age Piano obsolete and the patent worthless by December 31, 2018. Prepare all journal entries required in 2017 and 2018. (Round answers to 0 decimal places, e.g. 8,564. Credit account titles are automatically indented when amount is entered. Do not indent manually. If no entry is required, select "No Entry" for the account titles and enter 0 for the amounts.) Account Titles and Explanation Debit Credit