30. President Ronald Reagan earned a yearly salary of 2 x 10^5 dollars as president. He served 8 years as president. What was the total amount of
money Ronald Reagan earned as president?
A 1.6 x 106 dollars
B. 2.0 x 106 dollars
c. 1.6 x 107 dollars
D. 2.0 x 107 dollars

How do i do this activity, is appreciated

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 0 a. at what time does the particle reverse direction? b. when is the displacement positive? (round one decimal place and answer in interval notation) c. when is the displacement negative? (round one decimal place and answer in interval notation) d. when is the particle’s acceleration positive? (round one decimal place and answer in interval notation) e. when is the particle’s acceleration negative? (round one decimal place and answer in interval notation)

Use sigma notation to represent the following series for 9 terms.