for this kind of problem you are going to want to get all the z's (or any variable) to one side and all the numbers to one side. to do this you have to do EVERYTHING to both sides, for this problem for instance you need to add 3 to both sides to isoate the z and get 40=z, also if this helps to orginize your thoughts you can flip the whole equation to be z=40, this last step is optinal andnot neccisary to get the problem right it just orginizes your thoughts. if you need further help let me know and ill do what i can.
