How do i solve x in a mathematics question

In order to solve for 'x' (or any variable in this matter!), you must isolate it.
In order to isolate it, you will probably have to do some of the following:
1. Addition
2. Subtraction
3. Division
4. Multiplication (Rarely used, only when there are fractions in play)

I'll give you a few examples of all of these in play.

x - 1 = 3
In this case, we must use addition to isolate x. Add 1:
x - 1 + 1 = 3 + 1
x = 4

Subtraction:
x + 1 = 2
In order to isolate x, we have to subtract both sides by 1:
x + 1 - 1 = 2 - 1
x = 1

Division:
2x = 4
In order to isolate x, we have to divide by 2:
2x/2 = 4/2
x = 2

Multiplication:
x/2 = 4
In order to isolate x, we have to multiply both sides by 2 to remove the denominator of the fraction
2*x/2 = 4 * 2
x = 8

Those are the most common ways of solving for a variable in a mathematics question. If you have a question, just ask. :)
Good luck!