Description: Sal solves the equation -16 = x/4 + 2. It takes two steps because he first has to subtract 2 from both sides and then multiply both sides by 4. Created by Sal Khan and Monterey Institute for Technology and Education. We have the equation negative 16 is equal to x over 4, plus 2. So we really just need to isolate the x variable on one side of this equation, and the best way to do that is first to isolate it, isolate this whole x over 4 term from all of the other terms. But if we want to subtract it from the right-hand side, we also have to subtract it from the left-hand side, because this is an equation.*Teacher Advisor is 100% free.