21/8 converted into a mixed number equals

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)

Which of the following parabolas opens down?

Darren earned $663.26 in net pay for working 38 hours. he paid $118.51 in federal and state income taxes, and $64.75 in fica taxes. what was darren's hourly wage? question options: $17.45 $19.16 $20.57 $22.28