I need help understanding this and how to do it :)​

Two variables, x and y, vary inversely, and x=12 when y=4. what is the value of y when x=3?

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)

Does anyone know how to solve and graph this: 4 + | a + 2 | < 7the only part i don't get is the "4 +"