x + 4 (This is the original expression.)
2 + 4 (Substitute (replace) x with 2)
6 (Add. The answer is 6).
In this section, you will review the definitions of variables and constants.
A variable is a letter or other symbol that is used in a mathematical expression to represent a value that can change or vary. When a value does not change it is considered to be constant.
In the expression x + 4, x is considered a variable because it may represent many different values.
For example, find the answer using the above expression if x is 2? Click the links below to check your answers.
Interactive popup. Assistance may be required.x + 4 (This is the original expression.)
2 + 4 (Substitute (replace) x with 2)
6 (Add. The answer is 6).
Now given the same expression, find the answer if x is 10.
Interactive popup. Assistance may be required.
x + 4 (This is the original expression.)
10 + 4 (Substitute (replace) x with 10)
14 (Add. The answer is 14).