Lesson 3-2 -- Solving Inequalities using Addition & Subtraction

1. Lesson 3-2 -- Solving Inequalities using Addition & Subtraction Objectives: To use addition and subtraction to solve inequalities.

2. Real-World Connection • Solving inequalities can help with problems involving safe loads on chair lifts or fair rides, as seen in Example 4.

3. STEPS(same as when solving equations) • Get variable on one side by itself by performing the inverse operation. • Graph the solution on a number line. • Verify your solution.

4. Vocabulary & Properties • equivalent inequalities – have same solutions for example: x + 4 < 7 and x < 3 • Addition Property of Inequality For every real number a, b, and c, if a > b then a + c > b + c; if a < b then a + c < b + c. • Subtraction Property of Inequality For every real number a, b, and c, if a > b then a - c > b - c; if a < b then a - c < b - c. These properties are also true for < and >.

5. Example 1, page 140 • Solve m – 6 > - 4 and graph the solution. • To check: Choose a number from your graphed solution and substitute it in the original inequality to verify you have solved correctly.

6. Example 2, page 141 • Ex. 2) Solve n – 7 < -2 and graph the solution.

7. Example 3, page 142 • Ex. 3) Solve & graph t + 3 > 8.

8. Example 4, page 142 • Your baseball team has a goal to collect at least 160 blankets for a shelter. Team members brought in 42 blankets on Monday and 65 on Wednesday. How many blankets must the team donate on Friday to make or exceed their goal?

9. Summary • What did you learn today?

10. Summary • How do I solve inequalities with addition and subtraction? • How do I graph the solution to the inequality? • How do I verify your solution?

11. ASSIGNMENT • #3-2, page 142 every 3rd 3–84, and every 3rd 93-120