How many seconds are in a day if u subtract them from yesterday how many are left

Equation for the calculation double 2 and then add 5

Two airplanes start at the same place and travel in opposite directions,one at 395 miles per hour and the other at 422 miles per hour. how many hours will it take for the planes to be 2451 miles apart?

Interpret the following expression (5y^2-7)^3/(2y)^2