Answer: Yes it is a solution. It is the only solution to this equation.
To confirm this statement, replace every x with 4 and then use PEMDAS to simplify both sides
2*x = 8 is the original equation
2*4 = 8 is what happens after we replace x with 4
8 = 8 is the final result after simplifying everything
We get the same thing on both sides (8) so that confirms that x = 4 is indeed the proper solution.