Which expression is equivalent to 2x-3y

On any given day, the number of users, u, that access a certain website can be represented by the inequality 1125-4530 which of the following represents the range of users that access the website each day? u> 95 or u < 155 95> u> 155 u< 95 or > 155 95

Monica build a remote control toy airplane for science project to test the plane she launched it from the top of a building the plane travel a horizontal distance of 50 feet before landing on the ground a quadratic function which models the height of the plane in feet relative to the ground at a horizontal distance of x feet from the building is shown

What is the number 321,000,000 in scientific notation? also what is the number? ?