Example

Graphing x1x \leq 1, x<5x < 5, and x>1x > -1 on a Number Line

To graph each inequality on a number line, identify the boundary value, choose the correct endpoint symbol, and shade in the appropriate direction:

  • x1x \leq 1: The solution set contains every number that is 11 or less. Shade all values to the left of 11 and place a bracket (or closed circle) at x=1x = 1 to show that 11 itself is included in the solution set.
  • x<5x < 5: The solution set contains every number less than 55, but not 55 itself. Shade all values to the left of 55 and place an open parenthesis (or open circle) at x=5x = 5 to indicate that the endpoint is excluded.
  • x>1x > -1: The solution set contains every number greater than 1-1, but not 1-1 itself. Shade all values to the right of 1-1 and place an open parenthesis (or open circle) at x=1x = -1 to show it is excluded.

These three cases illustrate the two key decisions in graphing any single-variable inequality: the direction of shading (left for << or \leq, right for >> or \geq) and the endpoint symbol (bracket or closed circle when the endpoint is included; parenthesis or open circle when it is not).

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Updated 2026-04-21

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Ch.2 Solving Linear Equations and Inequalities - Elementary Algebra @ OpenStax

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