How can you solve problems involving equivalent expressions?

Setting expressions equal to one another gives us an equation.

In an equation, our goal is to isolate the variable; we must "undo" everything that has been done to the variable. We work backward; the last thing done to the variable will be the first thing we undo.

We "undo" things by performing the opposite operation; for instance, if the last thing done to our variable was that 3 was subtracted from it, we would undo that first by adding 3 to both sides.

What we do to one side we must do to the other in order to preserve equality.

We would continue this process of working backward until the variable was isolated; this would give us our solution.