Objective

• The goal is to provide an environment in which students can visualize that only one value of x can make the following equation true:
  x + a = b

  Thus, we can conclude that there is only one solution for this type of equation.

User´s Guide

1. Use the slider "Variable x" to change the value of x.
2. Use the slider "Variable a" to change the value of a.
3. Use the slider "Variable b" to change the value of b.

1. The default setting satisfies the equation x + 5 = 8. Use the slider "Variable x" to change x to a different value. Does the equation x + 5 = 8 still hold true after you change x to a value other than the default 3?

2. Change a to a different value. In this experiment, make sure a is smaller than b. Adjust x to various values. Are there many x values that can make the equation true?

3. Change b to a different value. In this experiment, make sure b is larger than a. Adjust x to various values. Are there many x values that can make the equation true?