Example 1

A clown at a birthday party can blow up 5 balloons per minute. The relationship between the number of balloons inflated and the time that has passed can be expressed with the equation y = 5x, where x is the number of minutes passed and y is the number of balloons inflated. Find the domain and range of this relationship.

In this example, the independent, or x, variable is the number of minutes. The possible x-values include all real numbers greater than or equal to 0, since time can be measured in fractional parts of a minute.

The dependent, or y, variable is the number of balloons inflated. The possible y-values include all real numbers greater than or equal to 0.

D: {x > 0}; R {y > 0}