Algebra 1 · Grades 8 to 9
Solving linear equations
Isolate the variable one step at a time.
The idea
Solving an equation means finding the value that makes the two sides equal. You undo operations one at a time until the variable is alone.
Whatever you do to one side, do to the other side. Undo addition and subtraction first, then undo multiplication and division.
Worked examples
- How to Solve 2x + 3 = 11 Solve the two-step equation 2x + 3 = 11 in four steps. See the answer, why each step is allowed, and the mistakes to avoid.
- How to Solve an Equation with Variables on Both Sides Solve 5x - 4 = 3x + 8 in five steps. Collect the variables on one side, then check the answer in the original equation.
- How to Solve a System of Equations by Substitution Solve y = 2x + 1 and 3x + y = 11 by substitution. Five steps, the reason for each one, and the substitution mistakes to avoid.
Practice this topic
4 problems with answers.