First, you develop, so you get:
Then, you put known numbers (numbers without x) apart, and unknown numbers (numbers with x) apart. And remember, moving from a side to another change the sign of the Number (Positive become negative, and negative become positive) so you get:
Now, you do the calculations, you get:
Then, you move 11 to the other side. And since it was in a multiplication equation, it become a division. So you get:
Hope this Helps! :D