Strategy #6: Use Substitution to Check Your Work

Category: Algebra

After solving for a variable, plug your answer back into the original equation to verify it works. However, for better time management, mark problems to be checked and return to them once you’ve finished all the problems.

Why it matters: Algebra errors are easy to make under pressure. Substituting your answer takes 10 seconds and can save you from a wrong answer you feel confident about.

When it's especially useful: Systems of equations, quadratic equations (where extraneous solutions can appear), and any problem where you performed multiple steps.

Practice tip: Make substitution-checking a habit on every algebra problem, not just when you're unsure. The SAT includes trap answers designed to look right but fail the check.