If 75 minutes is considered 20% of what the recommended amount of exercise is what is 100%?

Question 5 spring semester final exam math evaluate

Solve for x and y: 217x + 131y = 913; 131x + 217y = 827

The position of a moving particle is given by the position function: f(t)=-9t-t^2-0.2t^3+0.1t^4 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)