Domain and Range of a Function Given Their Equation

Identify the range of the following function when given the domain { 2, 3, 10}:
y = 4x - 12

• 4, 12, 20

• -20, 0, 28

• -4, 0, 28

• 8, 12, 40

Janice is working as a babysitter for the Harold Family.  They plan to leave for their date at 7:00 pm  and be back by 12:00 am.  If the equation f(x) = 15x + 20 models the amount that Janice will earn, where x is the number of hours she works, and f(x) is the total money she earns, what is an appropriate domain?

• any value between 0 and 5

• any value between 15 and 20

• any value between -1 and 1

• any value greater than 0

Janice is working as a babysitter for the Harold Family.  They plan to leave for their date at 7:00 pm  and be back by 12:00 am.  If the equation f(x) = 15x + 20 models the amount that Janice will earn, where x is the number of hours she works, and f(x) is the total money she earns, what is an appropriate range?

• any value between 0 and 20

• any value between 0 and 125

• any value between 0 and 95

• any value greater than 0

What is the range of the following function, if the domain is {1,7,10}? 
f(x) = x + 4

• {-3,3,6}

• {1,7,10}

• {5,11,14}

• {4,28,40}

A student borrowed $480 from a friend. He agreed to make monthly payments of $96 with no interest until the loan balance was paid off. The function shown models this situation, where f(x) represents the remaining loan balance in dollars after the student has made x monthly payments. Which statements are true about the domain and range of the function for this situation? Select the correct answers.

• D: {0, 1, 2, 3, 4, 5}

• R: {0, 96, 192, 288, 384, 480}

• D: all real numbers

• R: {0, 1, 2, 3, 4, 5}

• : {0, 96, 192, 288, 384, 480}

• D: {0, 96, 192, 288, 384, 480}

• R: all real numbers

Answer explanation

Domain - x values

Range - y values

Real-world examples = apply common sense and judgements

The height in inches of concrete being poured for a foundation can be found using the function y=15+2.5x, where x is the number of minutes. If the concrete is poured between 5 and 10 minutes, find the domain and range of this situation.

• Domain: {5, 6, 7, 8, 9, 10} Range: {28, 29, 30, ..., 40}

• Domain: {28, 29, 30, ..., 40} Range: {5, 6, 7, 8, 9, 10}

• All real numbers

• All non-negative integers

• All positive integers

• All non-negative real numbers

State the domain:

• (-oo, 4)

• (-oo, 2]

• [2, oo)

• [4, oo)

Find the domain.

• All Real Numbers

• {-2, 0, 2}

• {0, 3/2, 3}

• {0, 3, 2}

• {4, -3, 6}