Plus and Minus (Different Variables)
Theory
Different Variables
The only thing you have to remember here is that you don’t mix different variables. You don’t know what and are (the variables are substituted for an unknown number, so you don’t know which numbers the variables represent). You don’t know if , or if . Therefore, is just .
Example 1
Calculate and simplify
Here, there are two different variables, and . You have to calculate terms with and separately. Then you get
