Section 2-8 Inequalities and Their Graphs pages Graph Inequalities Write Inequalities

An inequality is a mathematical sentence that contains >, <, ≥, ≤, or ≠. Some inequalities contain a variable. Any number that makes an inequality true is a solution of the inequality. For example, -4 is a solution of y ≥ -5 because -4 ≥ -5.

Graphing Solutions of Inequalities a)x > -2 An open dot shows that –2 is not a solution. Shade all points to the right of -2.

Graphing Solutions of Inequalities b)w ≥ -5 Shade all points to the right of -5. A closed dot shows that –5 is a solution.

Graphing Solutions of Inequalities c)k ≤ 4 Shade all points to the left of 4. A closed dot shows that 4 is a solution.

Graphing Solutions of Inequalities d)y < 6 Shade all points to the left of 6. An open dot shows that 6 is not a solution.

Check Understanding Graph the solution of each inequality. a) z < -2 c) a ≤ -5 b) 4 > x d) 2 ≥ c

Writing Inequalities to Describe Graphs Write the inequality shown in each graph. a) b)

Writing Inequalities Food can be labeled very low sodium only if it meets the requirements established by the federal government. Use the table to write an inequality for this requirement. LabelDefinition Sodium-free foodLess than 5 mg per serving Very low sodium foodAt most 35 mg per serving Low-sodium food At most 140 mg per serving

= 35 mg sodium A serving of very low sodium Has at most Words number of milligrams of sodium in a serving of very low sodium food. v Let Equation 35 v ≤

Check Understanding Use the table in Example 3. A certain food is labeled sodium free. Write an inequality for n, the number of milligrams of sodium in a serving of this sodium free food.

Homework: pages 104 – 105, #s 2-12 even, 13-16, even, 27, 28, 37, You are expected to write the problems (except for word problems and multiple choice problems) and show all of your work on every problem. Failure to write the problems/show the work will result in either receiving partial or no credit.