If f(x) represents the number of hours required to travel x miles, what is the domain of the function, f(x)? x≥0
x is greater than or equal to 0
f(x)≥0
f of x is greater than or equal to 0

The value of
f(x)
can be any real number.
The value of f of x can be any real number.

Can somebody me out with this question

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)

Mis the midpoint of rq if rm equals 2x + 5 and mq equals 4x - 9 what is the length of rq