How to solve one-step and two-step equations
When you solve an equation, the goal is to get the variable by itself. We can undo one operation at a time, as long as we do the same thing to both sides. Let’s start with one step, then work backward through two.
Choose an inverse operation
Addition and subtraction undo each other. Multiplication by a nonzero number and division by that number undo each other. In , we undo the addition by subtracting from both sides.
Solve a one-step equation
In , subtracting is the only operation on . Add to both sides.
Check in the original equation. Substituting for gives , so the two sides agree.
Solve a two-step equation
In , we multiply by and then add . Work in reverse. Subtract first, then divide both sides by .
Check by plugging the answer into the original equation. We get , which is the value on the right side.
