Two small planes start from the same point and fly in opposite directions. The first plane is flying 50 mph slower than the second plane. In 3 h, the planes are 900 mi apart. Find the rate of each plane.

The domain of a function can be represented by which one of the following options? o a. a set of output values o b. a set of f(x) values o c. a set of input values o d. a set of both input and output values