What’s the error he made and the answer that’s all

Select all the correct answers. what is 221,000,000,000,000,000,000 expressed in scientific notation?

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)

Acompany made a profit of 75000 over a period of 6 years on an initial investment of 15000 what is the annual roi