Evaluating Functions (Graphs and Equations)

Evaluating Functions (Graphs and Equations)

Answer the following questions to review function evaluation!

F(x) = y

• Functions can be written using function notation: f(x) = or y =

• Remember, f(x) is read as "f of x"

• For example, f(x) = 3x + 4 is the same as y = 3x + 4.

• Both f(x) and y are two ways to represent output!

Desmos Calculator

Desmos can be used to evaluate functions!

See the example to the right using function notation and y =

Go to this website to access:

https://www.desmos.com/calculator

Multiple Choice

 $f\left(x\right)=x+2$  
Fill in the blank:  $f\left(-9\right)=$  _____

• -7

• -2

• -1

• 2

• None of These

Multiple Choice

If f(x) = 4x + 7, evaluate f(3).

• f(3) = 19

• f(3) = 14

• f(3) = 5

• f(3) = 12

Multiple Choice

Let y = x² + 5

Determine the value of y when x = -3

• -4

• -1

• 14

Use Desmos!

Don't forget the parenthesis.

Multiple Choice

Let y = -3x + 4.

Evaluate the function when x = 2.

• -2

• 3

• -1

Use Desmos!

Don't forget the parenthesis.

Evaluating Functions on a Graph

x-axis = input

y-axis = output

Multiple Choice

Evaluate f(2).

Click on the picture to make it larger.

• f(2) = 5

• f(2) = 12

• f(2) = 10

• f(2) = 0.5

Answer for previous slide

Multiple Choice

Evaluate for f(-5)

Click on the picture to make it larger.

• 1

• 0

• 2

• -2

Evaluate for f(-5)

Answer for previous slide

When x = -5, y = -2...

so: f(-5) = -2

Multiple Choice

Evaluate for f(1)

Click on the picture to make it larger.

• 0

• -3

• 3

• 2

Answer for previous slide

Multiple Choice

What is the value of f(0)?

Click on the picture to make it larger.

• -2

• 2

• 4

• 0

Answer for previous slide

Multiple Choice

_{Using the graph, what does f(8) equal?}

Click on the picture to make it larger.

• 8

• 2

• 1

• 0

F(8) = ? (Answer for previous slide)

After 8 hours, Denise is 1 mile from home.

Multiple Choice

What does H(5) =18 mean in the context of the problem?

Click on the picture to make it larger.

• The height of the plant after 5 weeks is 18 inches

• The height of the plant after 18 weeks is 5 inches

• The height of the plant is 5 inches after 18 weeks

• The height of the plant is dependent on the week it was planted

Multiple Choice

What does f(1990)=214 mean in the context of the problem?

• In 1990 there were 214 million people with health insurance

• In 214, there were 1990 people with health insurance

• When there are 1990 people, the year is 214

• None of these

Multiple Choice

The function c(m) = 1.45m + 3.50 represents the cost of a taxi for m miles.
What does c(7) represent?

• A cost of $7 to ride the taxi
• The cost to ride 7 miles
• The minimum distance to ride a taxi
• The minimum cost of a taxi

You have completed the quizizz!

If you have any more questions, let your teacher(s) know.