Home > Grade Levels > Grade 8 >

Analyzing Functional Relationships by Graphing

Answer Keys Here

Aligned To Common Core Standard:

Grade 8 Functions - 8.F.B.5

How to Analyze Functional Relationships by Graphing - Analyzing a functional relationship is not as difficult as it may seem, and yet many Grade 8 students often find it daunting. Using the right examples backed up by the right theoretical understanding can make analyzing functional relationships easier. A relation is simply a set of all the ordered pairs. Remember, not all relations are functional relationships. A function exists when each x-value (independent value, input) paired with exactly one y-value (dependent value, output). This sort of pairing is referred to as a functional relationship. To understand a functional domain, you need to understand what a function is. A function is when each member of the domain is associated with just one of the members of the range. There is another way of analyzing a functional relation. If you can make a straight vertical line that can touch two or more points on the graph simultaneously, it means that the relationship is not functional.

Printable Worksheets And Lessons

Homework Sheets

You will find out very quickly how far along students are with understanding what graphs actually mean with this skill.

  • Homework 1 - The graph has three stages that go along with the story we have been presented with.
  • Homework 2 - Describe the graph of the function between x = 4 and x = 8. We can plot this function in graph. Since there is no value for y, they are just vertical linear graphs at those x coordinates.
  • Homework 3 - If the rate of change is constant. So it is a linear function.

Practice Worksheets

It is all about understanding what the graphs mean and what they tell us about the variables.

  • Practice 1 - Describe the graph of the function. Does the graph display a linear relationship?
  • Practice 2 - Jimmy walks to the park in early morning and runs around. After running in the park, he goes home using a bicycle. During which activity is Jimmy moving at the fastest rate?
  • Practice 3 - Interpret the the data chart to find a relationship.

Math Skill Quizzes

We look at the data from all types of angles here.

  • Quiz 1 - Describe the graph of the functions between x = 6 and y = 5.
  • Quiz 2 - Interpret the lines that you see.
  • Quiz 3 - Break apart the graph and explain the trend that you see.