so this is called a one step equation so in that case...
you are wanting to isolate the variable x so the length of one side is going to be x for this equation. So first you "have" to get x by itself in order to do to that you will want to either subtract 20 from both sides which will leave you with -10 and you don't want that so you will have to divide 10 from both sides to get x=.5
I will attach what i did to get your answer in the attachment below. Hope this helps! Good Luck!
