Need finding the value of x and y. by showing and explaining step by step so i understand it you! : )

What is the name used to describe a graph where for some value of x, there exists 2 or more different values of y?

Factor the expression using gcf 9b+45

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)