Sylvia earns $7 per hour at her after school job. After working one week, she received a paycheck for $91.

Write an equation to find the number of hours Sylvia worked to earn $91. Use a variable.

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)

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?

There are a total of 75 students in the robotics club and science club. the science club has 9 more students than the robotics club. how many students are in the science club?