What slope of the points (9,7) and (3,3)

The last time i bought this product , it cost $20.00 but it looks like it cost 29. 60 today? what is the increase

What is the result of adding the system of equations? 2x+y=4 3x-y=6

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)