30 POINTS
2. What is the product of -2x^3+x-5 and x^3-3x-4 ?
(a) Show your work.
(b) Is the product of -2x^3+x-5 and x^3-3x-4 equal to the product of x^3-3x-4 and -2x^3+x-5? Explain your answer.

Awater holding tank measures 105 m long, 50 m wide, and 8 m deep. traces of mercury have been found in the tank, with a concen- tration of 60 mg/l. what is the total mass of mercury in the tank? answer in units of kg.