What is the key rule to remember when solving inequalities involving multiplication or division by a negative number?

You must flip the inequality sign when multiplying or dividing by a negative number.

Solve the inequality: -3x < 12. Graph your solution on a number line.

x > -4. The graph should show an open circle at -4 and an arrow pointing to the right.

x ≤ -10. The graph should show a closed circle at -10 and an arrow pointing to the left.

x > 20. The graph should show an open circle at 20 and an arrow pointing to the right.

x ≤ 5. The graph should show a closed circle at 5 and an arrow pointing to the left.

9th GradeMath50 min

I can solve inequalities using multiplication and division, and graph the solutions on a number line.

8 min

5 2 Solving Inequalities with Multiplication and Division

Megan Tompkins

10 min

Key concepts students will learn:

•
When solving inequalities, if you multiply or divide both sides by a negative number, you must flip the inequality sign.
•
To solve an inequality with a fraction multiplied by a variable, multiply both sides by the reciprocal of the fraction.
•
The phrase 'at most' translates to ≤, while 'at least' translates to ≥ when writing inequalities from word problems.

15 min

11 questions • Multiple choice & Short answer

5 min

“Solve for x: -¾x < -9. Graph the solution on a number line.”

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