Ok. So in Algerbra you are supposed to do some really complicated things. But when it's like that, where the 25 is multiplied by g. You will do the opposite which is dividing. I would recommend some Khan Academy. Even though it can be annoying. It will help you solve problems like this and it will build up your speed. So, summed up you will divide 200 and 25. Which equals 8. Hope that helps!