AlgebraLab

Algebra I Recipe: Graphing Linear Equations with One Variable

By G Redden

1.
A. The Coordinate Plane
  1. x-axis – the horizontal axis
  2. y-axis – the vertical axis
  3. origin – the point where the x and y axis intersect……(0, 0)
  4. quadrants – the four “corners” of the coordinate plane.
    • Quadrant I – top right
    • Quadrant II – top left
    • Quadrant III – bottom left
    • Quadrant IV – bottom right
  5. positive numbers – numbers to the right of the origin on the x-axis and numbers above the origin on the y-axis.
  6. negative numbers – numbers to the left of the origin on the x-axis and numbers below the origin on the y-axis.
B. Graphing an Ordered Pair like (-2, 6), where the x-value is always the first number and the y-value is always the second number.
  1. Move right or left from the origin.
    • Right – if the x-value is positive.
    • Left – if the x-value is negative.
  2. Move up or down from the x-value.
    • Up – if the y-value is positive.
    • Down – if the y-value is negative.
  3. Mark your point after making the two moves.
C. Graphing Horizontal and Vertical Lines
  1. y = c (c being any #) is a horizontal line through the ordered pair (0, c).
    • For example, y = -2 is a horizontal line through the ordered pair (0, -2).
  2. x = c (c being any #) is a vertical line through the ordered pair (c, 0).
    • For example, x = 5 is a vertical line through the ordered pair (5, 0).