Which steps can be taken to translate the phrase “the height of a tree is increased by seven inches” into an algebraic expression? Check all that apply. Replace “the height of a tree” with a variable, x. Replace “seven inches” with a variable, x. Replace “increased by” with an addition symbol. Replace “seven inches” with 7. Replace “increased by” with a multiplication symbol. Replace “the height of a tree” with 7. Write the expression x + 7. Write the expression x times 7.

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 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)