As we can see, f(x) = 2x, and g(x) is also equal to 2x. Lets try substituting a few values for x to see if we can make f(x) = g(x) a true statement. Lets try 1. 2(1) =2. And 2(1) = 2 as well. Therefore for the value of 1, f(x) = g(x). Now lets try 2. 2(2) = 4, and 2(2) = 4 as well. Therefore for the value of 2, f(x) = g(x). Also, I substituted the values into x, FYI, cause they are asking what values of x. I did this to show you that any value can work for x. Therefore all your answers would be correct, unless they are not a real number. They are the same expressions, so you should have the same solution for any answer.
Since this was kind of long, to summarize, the answer would be, X can be any real number because the equations are equal to each other.
Hope this helps! :D
