Specific scenarios such as strong evidence stars an inductive argument . It is completed with a conclusion (likely to be true). It is a logical reasoning that allows a conclusion to be untrue. It is called a "valid guess".
The answer is any value that you put in for x would make the equation true. When you simplify the whole equation it looks like this: 2x - 6 = 2x - 6, therefor you could replace x with any value.