Writing Equations of Lines - Lesson Plan

Teaching Plan

Review Slope, x-Intercept, and y-Intercept (30 Minutes)

The objective of this section is to review the concepts of slope, x-intercept, and y-intercept in preparation for further instruction on writing linear equations.

Draw the graph of a line on the board. Review with students how to determine, by looking at the graph, the x-intercept, y-intercept, and slope of the line. (5 minutes) Write the equation for the line in slope-intercept form below the graph. Describe how the slope and y-intercept can be determined by looking at the equation. (5 minutes)
Using a computer projector, demonstrate how to go to the eNLVM website, go to your school and class, and login. (10 minutes) Demonstrate how to do the first activity in the Slope-Intercept Formula section and how to move between activities. (5 minutes)
Ask students to login and complete the Review of Intercepts and Slopes section. This section will serve as a warm-up activity, asking students to identify, by looking at a graph, the x-intercept, y-intercept, and slope of a line. If students finish early, have them begin working on the Slope Intercept Formula section.

Introduce Linear Equations in Slope-Intercept Form (50 Minutes)

Ask students to complete the Slope Intercept Formula section. This introduces students to linear equations in slope-intercept form. Students are given practice exercises in which they must determine the equation of a line based on a given set of points, a slope, and/or a y-intercept. (20 minutes)
When students have finished working through the section, login to the eNLVM on the computer connected to the projector. Together as a class, complete Activity 7: Writing a Linear Equation from Slope and a Point and Activity 9: Writing a Linear Equation from Two Points. Address student questions and review key concepts. (10 minutes)
Ask students to complete the Quiz. (10 minutes)
With the time remaining, review the Quiz questions as a class, addressing problem areas and reinforcing key concepts. (5-10 minutes)

Assessment

• Use class discussions to gauge the progress of the class and to identify common misconceptions.
• Walk around and observe individual students while they go through the lesson to identify individual progress and challenges.
• Use the quiz for the purpose of summative assessment and grading.

Credits

Correlation to Standards

Correlation to NCTM Standards

Algebra - Standard 2. Represent and analyze mathematical situations and structures using algebraic symbols.

• Grades 6-8
• Explore relationships between symbolic expressions and graphs of lines, paying particular attention to the meaning of intercept and slope.

Correlation to Utah Standards

• PreAlgebra - 2.2.3: Determine the slope of a linear relation from a graph or ordered pairs.
• Elementary Algebra - 2.1.2: Represent linear equations in slope-intercept form, y = mx + b, or standard form, ax + by = c.
• Elementary Algebra - 2.3.1: Identify the slope of a line when given

  a.  A set of two ordered pairs.
  b.  An equation of a linear function.
  c.  The graph of a linear function.

• Elementary Algebra - 2.3.2: Write the equation of a line when given:

• Elementary Algebra - 2.3.8: Graph linear functions using the slope-intercept form of a line.

• PreCalculus - 2.2.7 Find the x- and y-intercepts, zeros (roots), maxima, and minima of functions.

Correlation to Arizona Standards

• Grade 8 - Strand 3, Concept 4, PO 1: Identify the slope of a line as the rate of change (the ratio of rise over run).
  
• High School - Strand 3, Concept 3, PO 6: Write a linear equation for a table of values.
• High School - Strand 3, Concept 3, PO 10: Write an equation of the line given: two points on the line, the slope and a point on the line, or the graph of the line.
• High School - Strand 3, Concept 4, PO 1: Determine slope, x-, and y-intercepts of a linear equation.