This is actually a very simple problem when you understand how to do it.
First, I would add the 12 to both sides.
Equation would now look like this x/6=24
Then I would do the inverse (opposite) of division which is multiplication.
So multiply 6 to both sides so we can get the x alone. 6*12=144
Now x is alone, and X = 144.
Feel free to ask me questions!