Find the foci of each hyperbola graph the hyperbola y^2/400 - x^2/169 =1

How to solve a simultaneous equation involved with fractions?

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)

Can you make 1000, using only eight 8’s? if you had your choice, would you rather have 5 million dollars, or 1 penny, doubled every day for a month?