a. The first variable is x and the second variable is y.
b. The equations are and
Step-by-step explanation:
Step 1:
The first step is to define the variables. The variables can be any two symbols, letters, characters, etc.
Here let the first variable be x and the let the second variable be y.
So the variables are defined as x and y.
Step 2:
The sum of the given variables is 12.
The first variable + the second variable = 12,
The difference between the two variables is 4.
The first variable - the second variable = 4.
Step 3:
If we add both the equations we get, and
x = 8 and y = 4.