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Understanding Graphing Linear Inequalities

Dec 4, 2024

Graphing Linear Inequalities

Overview

  • Learn how to graph linear inequalities.
  • Five problems increasing in difficulty.
  • Discuss solution sets.
  • Handle lines not in y=mx+b form.
  • Interactive problem for viewers.
  • Printable notes available in the video description.

Graphing Inequalities

Problem 1: y ≥ -2

  • Graph the line: y = -2
    • y controls vertical position (y-axis).
    • A horizontal line representing y = -2.
  • Inequality: y is greater than or equal to -2
    • Shade the region above the line.

Problem 2: x < 4

  • Graph the line: x = 4
    • x controls horizontal position.
    • A vertical dotted line at x = 4 because x cannot equal 4.
  • Inequality: x is less than 4
    • Shade the region to the left of the line.

Problem 3: y ≥ x + 3

  • Form: y = mx + b, slope (m) = 1, y-intercept (b) = 3
  • Graph the line: y = x + 3
    • Solid line because of '≥'.
    • Start at y-intercept (0,3), slope of 1 (up 1, right 1).
  • Inequality: y is greater than or equal to x + 3
    • Shade the region above the line.

Problem 4: y < 2x - 4

  • Slope and intercept: m = 2, b = -4
  • Graph the line: y = 2x - 4
    • Dotted line (y cannot equal 2x - 4).
    • Start at y-intercept (0,-4), slope of 2 (up 2, right 1).
  • Inequality: y is less than 2x - 4
    • Shade the region below the line.
  • Solution set: All (x, y) pairs in the shaded region.
    • Example check: Point (5,4) is in the solution set.
    • Point (0,-1) is not.

Problem 5: 3y ≤ 6 - x

  • Reform the inequality: y ≤ -1/3 x + 2
  • Graph the line: y = -1/3x + 2
    • Solid line because of '≤'.
    • Start at y-intercept (0,2), slope of -1/3 (down 1, right 3).
  • Inequality: y is less than or equal to -1/3x + 2
    • Shade the region below the line.

Interactive Problem

  • Graph: x - 2y < 8
    • Determine if it should be a solid or dotted line.
    • Identify slope and y-intercept.
    • Decide shading direction.
  • Comment a solution with one point in and one outside the solution set.

Additional Resources

  • Printable notes with QR codes available in description.
  • Subscribe for more content.

Conclusion

  • Quick review of graphing linear inequalities.
  • Encouragement to engage with provided practice problem.
  • Notes and subscription reminder.