Inverse operations are two operations that undo one another. For example, adding $6$ and subtracting $6$ are inverse operations because they cancel each other out. This means that adding $6$ to any number and then subtracting $6$ results in the original number. Equations are solved by using inverse operations. By the Properties of Equality, any operation performed on one side of an equation must also be performed on the other side of the equation to maintain equality. Consider an example. This equation can be solved by adding $4$ to both sides. In this case, the subtraction on the left-hand side of the equation can only be eliminated by adding $4$ on both sides. The result of applying the Properties of Equality on an equation is an equivalent equation.