1. Holt Algebra 1 3-2 Solving Inequalities by Adding or Subtracting 3-2 Solving Inequalities by Adding or Subtracting Holt Algebra 1 Warm Up Warm Up Lesson Presentation Lesson Presentation Lesson Quiz Lesson Quiz

2. Holt Algebra 1 3-2 Solving Inequalities by Adding or Subtracting Warm Up Graph each inequality. Write an inequality for each situation. 1. The temperature must be at least –10°F. 2. The temperature must be no more than 90°F. x ≥ –10 x ≤ 90 Solve each equation. 3. x – 4 = 10 14 4. 15 = x + 1.1 13.9 –10 0 10 –90 0 90

3. Holt Algebra 1 3-2 Solving Inequalities by Adding or Subtracting Solve one-step inequalities by using addition and subtraction Objectives

4. Holt Algebra 1 3-2 Solving Inequalities by Adding or Subtracting Solving one-step inequalities is much like solving one-step equations. To solve an inequality, you need to isolate the variable. Use an inverse operation to “ undo ” the operation in an inequality.

5. Holt Algebra 1 3-2 Solving Inequalities by Adding or Subtracting Using Addition and Subtraction to Solve Inequalities Solve the inequality and graph the solutions. x + 12 < 20 –10 –8 –6–4 –2 0246810 d – 5 > –7 –10 –8 –6–4 –2 0246810

6. Holt Algebra 1 3-2 Solving Inequalities by Adding or Subtracting Solve the inequality and graph the solutions. 0.9 ≥ n – 0.3 0 1 2 Using Addition and Subtraction to Solve Inequalities > –3 + t –10 –8 –6–4 –2 0246810

7. Holt Algebra 1 3-2 Solving Inequalities by Adding or Subtracting Since there can be an infinite number of solutions to an inequality, it is not possible to check all the solutions. You can check the endpoint and the direction of the inequality symbol. The solutions of x + 9 < 15 are given by x < 6.

8. Holt Algebra 1 3-2 Solving Inequalities by Adding or Subtracting What if … ? Harold wants to try to break the school bench press record of 282 pounds. He currently can bench press 250 pounds. Write and solve an inequality to determine how many more pounds Harold needs to lift to break the school record. Check your answer.

9. Holt Algebra 1 3-2 Solving Inequalities by Adding or Subtracting Lesson Quiz: Part I Solve each inequality and graph the solutions. 1. 13 < x + 7 x > 6 2. –6 + h ≥ 15 h ≥ 21 3. 6.7 + y ≤ –2.1 y ≤ –8.8

10. Holt Algebra 1 3-2 Solving Inequalities by Adding or Subtracting Lesson Quiz: Part II 4. A certain restaurant has room for 120 customers. On one night, there are 72 customers dining. Write and solve an inequality to show how many more people can eat at the restaurant. x + 72 ≤ 120; x ≤ 48, where x is a natural number