Strategy #9: Solve Linear Inequalities Carefully

Category: Algebra

Solve inequalities like equations, with one critical rule: flip the inequality sign when you multiply or divide by a negative number.

 

Why it matters: Forgetting to flip the sign is an extremely common error. The SAT exploits this.

 

Example: −2x > 8 → divide both sides by −2 → x < −4 (sign flips!)

 

Graphing on a number line:

• Strict inequality (< or >) → open circle

• Non-strict (≤ or ≥) → closed (filled) circle

 

Practice tip: Before finalizing, ask yourself: "Did I multiply or divide by a negative at any step?" If yes, double-check that you flipped the sign.

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Strategy #8: Recognize When a System Has No Solution or Infinite Solutions