Here is your equation:

You're trying to find x alone. To find a specific variable, you have to do the opposite of what's happening to the variable, which is x in this equation.
In this equation, x is being multiplied by a. That means you have to do the opposite of multiplying, which is dividing by a. To leave x alone, divide both sides by a.

Now that you have divided both sides by a, which leaves x alone, you have:

Your answer is

If you have any questions, feel free to ask in the comments! :)