Skip to lesson

Choose “Save as PDF” in the print dialog to keep a copy.

Cogito

Algebra 1 · Chapter 3 · Lesson 2

Practice Worksheet

Deciding What Is a Function

One input, one output — never two.

11 problems · about 21 minutes · F-IF.A.1

NameDate

Figure — use these to answer the problems

A straight line passes the vertical line test at every point.
-10-10-5-5551010
y = x
Slope1
Intercept0
Figure 1

Warm Up

Straightforward practice. Get the method working first.

4 problems

  1. Input 3 maps to both 1 and 8. Function? 1 for yes, 0 for no.

    Answer

  2. A vertical line crosses a graph twice. Function? 1 for yes, 0 for no.

    Answer

  3. A horizontal line crosses a graph twice. Function? 1 for yes, 0 for no.

    Answer

  4. Is a circle a function? 1 for yes, 0 for no.

    Answer

Build It Up

The same ideas with more to keep track of.

3 problems

  1. Is y = 5 a function? 1 for yes, 0 for no.

    Answer

  2. Sort each relation by whether it is a function.

    Write each item under the heading it belongs to: y = 2x · x = 3 · y = x² · A circle

    A function

    Not a function

  3. Is x = 2 a function? 1 for yes, 0 for no.

    Answer

Stretch Yourself

Mixed problems. Work out what kind of question it is before you start.

4 problems

  1. Inputs 1, 2, 3 map to 4, 4, 4. Function? 1 for yes, 0 for no.

    Answer

  2. How many outputs may one input have in a function?

    Answer

  3. The Repeat

    Input 4 maps to both 7 and 9. Is it a function? 1 for yes, 0 for no.

    Answer

  4. The Shared Output

    Inputs 2 and 5 both map to 8. Is it a function? 1 for yes, 0 for no.

    Answer