Let's imagine that we have the following function function:
[tex]y = x ^ 2 [/tex]
We have to:
Independent variable: x
Dependent variable: y
For x = -1:
[tex]y = (- 1) ^ 2 = 1 [/tex]
For x = 1:
[tex]y = (1) ^ 2 = 1 [/tex]
We observe that the independent variable can only obtain one result.