ALEX Classroom Resource

  

Manipulating Graphs

  Classroom Resource Information  

Title:

Manipulating Graphs

URL:

https://aptv.pbslearningmedia.org/resource/mgbh.math.ns.mangraph/manipulating-graphs/

Content Source:

PBS
Type: Audio/Video

Overview:

Watch how a graph is altered when key elements of the equation change. This lesson focuses on how to manipulate the equation of a line in slope intercept form to match the graphs provided deepening the understanding of both the slope and y intercept's role in the expression. This video was submitted through the Innovation Math Challenge, a contest open to professional and nonprofessional producers.

Content Standard(s):
Mathematics
MA2019 (2019)
Grade: 7
Accelerated
6. Interpret y = mx + b as defining a linear equation whose graph is a line with m as the slope and b as the y-intercept.

a. Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line in a coordinate plane.

b. Given two distinct points in a coordinate plane, find the slope of the line containing the two points and explain why it will be the same for any two distinct points on the line.

c. Graph linear relationships, interpreting the slope as the rate of change of the graph and the y-intercept as the initial value.

d. Given that the slopes for two different sets of points are equal, demonstrate that the linear equations that include those two sets of points may have different y-intercepts. [Grade 8, 9]
Unpacked Content
Evidence Of Student Attainment:
Students:
  • can analyze linear equations in the form y=mx + b as representing a line where m represents the rate of change, called the slope of the line when graphed. and b is the initial value, called the y-intercept when graphed.
  • Can create similar right triangles by connecting the "rise over run" between any two points on a given line and use them to show why their slopes are the same.
  • Can explain why any two points on a given line will have the same slope.
  • Can graph linear relationships on a coordinate plane when given in multiple contexts.
Teacher Vocabulary:
  • Slope
  • Rate of change
  • Initial Value
  • Y-intercept
Knowledge:
Students know:
  • how to graph points on a coordinate plane.
  • Where to graph the initial value/y-intercept.
  • Understand how/why triangles are similar.
  • how to interpret y=mx equations.
Skills:
Students are able to:
  • create a graph of linear equations in the form y = mx + b and recognize m as the slope and b as the y-intercept.
  • point out similar triangles formed between pairs of points and know that they have same slope between any pairs of those points.
  • Show that lines may share the same slope but can have different y-intercepts.
  • Interpret a rate of change as the slope and the initial value as the y-intercept.
Understanding:
Students understand that:
  • slope is a graphic representation of the rate of change in linear relationships and the y-intercept is a graphic representation of an initial value in a linear relationship.
  • When given an equation in the form y = mx + b it generally symbolizes that you will have lines with varying y-intercepts. even when the slope is the same.
  • you can use the visual of right triangles created between points on a line to explain why the slope is a constant rate of change.
Diverse Learning Needs:
Mathematics
MA2019 (2019)
Grade: 8
9. Interpret y = mx + b as defining a linear equation whose graph is a line with m as the slope and b as the y-intercept.

a. Use similar triangles to explain why the slope m is the same between any two distinct points on a non-vertical line in a coordinate plane.

b. Given two distinct points in a coordinate plane, find the slope of the line containing the two points and explain why it will be the same for any two distinct points on the line.

c. Graph linear relationships, interpreting the slope as the rate of change of the graph and the y-intercept as the initial value.

d. Given that the slopes for two different sets of points are equal, demonstrate that the linear equations that include those two sets of points may have different y-intercepts.
Unpacked Content
Evidence Of Student Attainment:
Students:
  • Analyze linear equations in the form y=mx + b as representing a line where m represents the rate of change, called the slope of the line when graphed. and b is the initial value, called the y-intercept when graphed.
  • Create similar right triangles by connecting the "rise over run" between any two points on a given line and use them to show why their slopes are the same.
  • Explain why any two points on a given line will have the same slope.
  • Graph linear relationships on a coordinate plane when given in multiple contexts.
Teacher Vocabulary:
  • Slope
  • Rate of change
  • Initial Value
  • Y-intercept
Knowledge:
Students know:
  • how to graph points on a coordinate plane.
  • Where to graph the initial value/y-intercept.
  • Understand how/why triangles are similar.
  • how to interpret y=mx equations.
Skills:
Students are able to:
  • create a graph of linear equations in the form y = mx + b and recognize m as the slope and b as the y-intercept.
  • point out similar triangles formed between pairs of points and know that they have the same slope between any pairs of those points.
  • Show that lines may share the same slope but can have different y-intercepts.
  • Interpret a rate of change as the slope and the initial value as the y-intercept.
Understanding:
Students understand that:
  • Slope is a graphic representation of the rate of change in linear relationships and the y-intercept is a graphic representation of an initial value in a linear relationship.
  • When given an equation in the form y = mx + b it generally symbolizes that there will be lines with varying y-intercepts. even when the slope is the same.
  • Use of the visual of right triangles created between points on a line to explain why the slope is a constant rate of change.
Diverse Learning Needs:
Essential Skills:
Learning Objectives:
M.8.9.1: Define linear functions, nonlinear functions, slope, and y-intercept.
M.8.9.2: Recall how to solve problems using the distributive property.
M.8.9.3: Recognize linear equations.
M.8.9.4: Identify ordered pairs.
M.8.9.5: Recognize ordered pairs.
M.8.9.6: Define similar triangles, intercept, slope, vertical, horizontal, and origin.
M.8.9.7: Recognize similar triangles.
M.8.9.8: Generate the slope of a line using given ordered pairs.
M.8.9.9: Analyze the graph to determine the rate of change.
M.8.9.10: Demonstrate how to plot points on a coordinate plane using ordered pairs from table.
M.8.9.11: Identify the slope-intercept form (y=mx+b) of an equation where m is the slope and y is the y-intercept.
M.8.9.12: Graph a function given the slope-intercept form of an equation.
M.8.9.13: Recognize that two sets of points with the same slope may have different y-intercepts.
M.8.9.14: Graph a linear equation given the slope-intercept form of an equation.

Prior Knowledge Skills:
  • Define ordered pairs.
  • Name the pairs of integers and/or rational numbers of a point on a coordinate plane.
  • Demonstrate when two ordered pairs differ only by signs, the locations of the points are related by reflections across one or both axes.
  • Identify which signs indicate the location of a point in a coordinate plane.
  • Recall how to plot ordered pairs on a coordinate plane.
Mathematics
MA2019 (2019)
Grade: 8
15. Compare properties of functions represented algebraically, graphically, numerically in tables, or by verbal descriptions.

a. Distinguish between linear and non-linear functions.
Unpacked Content
Evidence Of Student Attainment:
Students:
  • Describe the comparison of linear functions qualitatively and quantitatively by discussing and analyzing the rates of change (slopes), initial values (y-intercepts), and any points of intersection.
  • Tell the difference between functions that are linear and those that are non-linear by analyzing information in a variety of contexts.
Teacher Vocabulary:
  • Function
  • Linear
  • Non-linear
  • Slope
Knowledge:
Students know:
  • how to find rates of change and initial values for function represented multiple ways.
  • how to graph functions when given an equation, table, or verbal description.
Skills:
Students are able to:
  • identify the differences between functions represented in multiple contexts.
  • Tell the differences between linear and nonlinear functions.
Understanding:
Students understand that:
  • Converting to different representations of functions can assist in their comparisons of linear functions qualitatively and quantitatively.
Diverse Learning Needs:
Essential Skills:
Learning Objectives:
M.8.15.1: Define rate of change.
M.8.15.2: Recognize linear and nonlinear functions.
M.8.15.3: Recall how to read/interpret information from a table.
M.8.15.4: Identify algebraic expressions.
M.8.15.5: Recall how to name points on a Cartesian plane using ordered pairs.
M.8.15.6: Compare and contrast the differences between linear and nonlinear functions.

Prior Knowledge Skills:
  • Define expression, equivalent, and equivalent expressions.
  • Recall mathematical terms such as sum, difference, etc.
  • Recognize that a variable without a written coefficient is understood to have a coefficient of one.
  • Recall how to convert mathematical terms to mathematical symbols and numbers and vice versa.
  • Restate numerical expressions with words.

Alabama Alternate Achievement Standards
AAS Standard:
M.AAS.8.15 Identify linear and nonlinear functions graphically.


Mathematics
MA2019 (2019)
Grade: 8
Accelerated
23. Compare properties of two functions, each represented in a different way (algebraically, graphically, numerically in tables, or by verbal descriptions). Include linear, quadratic, exponential, absolute value, and linear piecewise. [Algebra I with Probability, 21, edited]

a. Distinguish between linear and non-linear functions. [Grade 8, 15a]
Unpacked Content
Evidence Of Student Attainment:
Students:
Given functions represented in various ways(algebraically, graphically, numerically in tables, or by verbal descriptions).
  • Use key features to compare the functions.
  • Explain and justify the similarities and differences of the functions.

  • Given a variety of functions in equation form, use logical reasoning to justify their classification as linear or non-linear by interpreting the relationships in the expressions.
Teacher Vocabulary:
  • Linear function
  • Exponential function
  • Quadratic function
  • Absolute value function
  • Linear Piecewise function
  • non-linear functions
Knowledge:
Students know:
  • Techniques to find key features of functions when presented in different ways.
  • Techniques to convert a function to a different form (algebraically, graphically, numerically in tables, or by verbal descriptions).
  • Characteristics of linear and nonlinear functions.
Skills:
Students are able to:
  • Accurately determine which key features are most appropriate for comparing functions.
  • Manipulate functions algebraically to reveal key functions.
  • Convert a function to a different form (algebraically, graphically, numerically in tables, or by verbal descriptions) for the purpose of comparing it to another function.
  • Compare functions based on their properties.
Understanding:
Students understand that:
  • Functions can be written in different but equivalent ways (algebraically, graphically, numerically in tables, or by verbal descriptions).
  • Different representations of functions may aid in comparing key features of the functions.
  • Functions are relationships between two variables that have a unique characteristic, that being, for each input there exists exactly one output.
  • Functions can be represented in a variety of ways (graphs, tables, and equations), each of which provides unique perspectives of the relationship between the variables.
  • Linear functions have a defining characteristic of a unit rate or slope that other nonlinear functions do not have.
Diverse Learning Needs:
Tags: equation, graphs, lines, slope, slope intercept form, yintercept
License Type: Public Domain
For full descriptions of license types and a guide to usage, visit :
https://creativecommons.org/licenses
AccessibilityVideo resources: includes closed captioning or subtitles
Comments

This resource contains the following activities:

Manipulating Graphs - Activity - can be found in the top right corner of the webpage. This is a printable activity. Just click on the link to be taken to the activity. 

What's My Line - Worksheet
  This resource provided by:  
Author: Kristy Lacks
Alabama State Department of Education