Straight Line Equations on a Graph

Introduction

• Understanding the basic components of a graph:
  • X-axis: Horizontal axis
  • Y-axis: Vertical axis
• Graph range: From -10 to +10 on both axes

Vertical Lines

• Equation form: x = constant
• Characteristics:
  • All points on the line have the same x-value
  • Example: If x = 4 for all points, the line is x = 4
• Other Examples:
  • x = 9
  • x = -2
  • To find the equation of a vertical line, observe where it crosses the x-axis

Horizontal Lines

• Equation form: y = constant
• Characteristics:
  • All points on the line have the same y-value
  • Example: If a line crosses the y-axis at 5, then y = 5
• Other Examples:
  • y = -3
  • If a line runs along the x-axis, then y = 0

Special Lines

• X-axis line: y = 0
• Y-axis line: x = 0

Diagonal Lines

• General form: y = x
  • All points have equal x and y coordinates (e.g., x = 6, y = 6)
• Inverted diagonal line: y = -x
  • The y-value is the negative of the x-value (e.g., x = 9, y = -9)

Conclusion

• Key takeaway: Recognize lines by their equation forms on graphs
• Closing: Encouragement to like and subscribe to the video

These notes summarize the key points on identifying and understanding straight line equations on a graph, focusing on vertical, horizontal, and diagonal lines.