Please answer 15 and 16. I got -5 for 15. Not sure if that's correct. Please show work

Questions 15-16: The annual net income for Sky High Electric Company for the period 2007-2011 could be approximated by the function P(t) =312 -24vt+60 billion dollars (2 s t s 6), where t is the time in years since 2005. Use this function to answer questions below. Question 15 10 Use the symmetric difference quotient (SDQ) to estimate the value of P'(3), using h = 0.0001 in the formula below. Include units with your answer. SHOW WORK in computing your value for work. Recall that, SDQ= P (3 + h ) - P ( 3 - h ) 2h Upload a scanned pdf file of your work for your answer to this question. Upload Choose a File Question 16 10 pts Interpret the value of P'(3) that you computed above. Your interpretation should have 3-parts as discussed in class and on the document about interpreting a derivative in the Files area of Canvas. Combine all three parts of your interpretation into a single sentence. If you were unable to compute a value in the last problem use 30.6 (which is not the answer to the previous question) for the value of P'(3) in this part