Respuesta :

26=w-12
+12  +12
38=w
That is your answer
Undo what has been done. First try to isolate the variable. So 12 is being subtracted by the variable. So you add 12 to each side. 
 26+12=w-12+12
Undo what has been done means to do the opposite of what is done. So now you are left with 38=w. If you added 12 to each side.