Graphing Linear Equations: Mastering Slope-Intercept Form

Algebra 2 Grades High School 10:30 Video

Lesson Description

Learn how to determine the equation of a line in slope-intercept form from its graph, including diagonal, horizontal, and vertical lines.

Video Resource

Equation of Line Slope intercept Form | Given Graph

Kevinmathscience

Duration: 10:30
Watch on YouTube

Key Concepts

  • Slope-intercept form (y = mx + b)
  • Slope (m) as rise over run
  • Y-intercept (b) as the point where the line crosses the y-axis
  • Identifying points on a graph
  • Horizontal and vertical lines equations

Learning Objectives

  • Students will be able to identify the slope and y-intercept from a graph of a linear equation.
  • Students will be able to write the equation of a line in slope-intercept form given its graph.
  • Students will be able to determine the equations of horizontal and vertical lines from their graphs.

Educator Instructions

  • Introduction (5 mins)
    Begin by reviewing the slope-intercept form of a linear equation (y = mx + b). Briefly discuss what slope (m) and y-intercept (b) represent. Show the video.
  • Guided Practice (15 mins)
    Work through the examples from the video, pausing at key points to ask students guiding questions. Focus on the two methods presented in the video: using the slope formula with two points and using one point with the y-intercept.
  • Independent Practice (15 mins)
    Provide students with graphs of linear equations and have them determine the equation in slope-intercept form independently. Include examples of diagonal, horizontal, and vertical lines.
  • Wrap-up (5 mins)
    Review the key concepts and address any remaining questions. Preview the next lesson on applications of linear equations.

Interactive Exercises

  • Graphing Tool
    Use an online graphing tool (e.g., Desmos, GeoGebra) to allow students to manipulate the slope and y-intercept of a line and observe how it changes the graph.
  • Collaborative Whiteboard
    Divide students into small groups and have them work together on a shared online whiteboard to find the equations of lines from given graphs.

Discussion Questions

  • What are the advantages and disadvantages of using the slope formula versus using the y-intercept and a single point to find the equation of a line?
  • How do you recognize horizontal and vertical lines on a graph? What are their equations?
  • Can all linear equations be written in slope-intercept form? Why or why not?

Skills Developed

  • Visual interpretation of graphs
  • Algebraic manipulation
  • Problem-solving
  • Critical thinking

Multiple Choice Questions

Question 1:

What is the slope-intercept form of a linear equation?

Correct Answer: y = mx + b

Question 2:

In the equation y = mx + b, what does 'm' represent?

Correct Answer: The slope

Question 3:

In the equation y = mx + b, what does 'b' represent?

Correct Answer: The y-intercept

Question 4:

What is the slope of a horizontal line?

Correct Answer: 0

Question 5:

What is the slope of a vertical line?

Correct Answer: Undefined

Question 6:

What is the equation of a horizontal line that passes through the point (0, -3)?

Correct Answer: y = -3

Question 7:

What is the equation of a vertical line that passes through the point (5, 0)?

Correct Answer: x = 5

Question 8:

A line passes through the points (1, 2) and (3, 6). What is its slope?

Correct Answer: 2

Question 9:

If a line has a slope of -2 and a y-intercept of 4, what is its equation?

Correct Answer: y = -2x + 4

Question 10:

Which of the following lines is parallel to y = 3x + 2?

Correct Answer: y = 3x - 4

Fill in the Blank Questions

Question 1:

The slope-intercept form of a linear equation is y = ___ + b.

Correct Answer: mx

Question 2:

The point where a line crosses the y-axis is called the ____.

Correct Answer: y-intercept

Question 3:

A line with a slope of zero is a ______ line.

Correct Answer: horizontal

Question 4:

A line with an undefined slope is a ______ line.

Correct Answer: vertical

Question 5:

The slope (m) can be calculated using the formula m = (y2 - y1) / (____ - x1).

Correct Answer: x2

Question 6:

A line that has the equation y = 7 has a y-intercept of _____.

Correct Answer: 7

Question 7:

A line has a slope of 5 and goes through point (0,3). Its equation is y = 5x ____ 3.

Correct Answer: +

Question 8:

The equation x = -2 represents a _______ line.

Correct Answer: vertical

Question 9:

If a line rises from left to right, it has a _____ slope.

Correct Answer: positive

Question 10:

If a line falls from left to right, it has a ______ slope.

Correct Answer: negative