**Section 9.1 Inequalities**

**Graphing Inequalities and Interval Notation**

Ex. Solve the inequality. Write answers in interval notation…

Ex. A cellphone company offers two different pay-as-you-go
plans: Plan A charges 20 cents

per minute while Plan B charges $7/month plus 10 cents per minute. Write an
inequality

and determine the number of minutes a person must exceed each month before Plan
B

becomes the most economical.

**Section 9.2 Compound Inequalities**

The intersection of two sets A and B is the set of all members that are in both set A and set B.

Ex. Let A = {1, 3, 7, 10, 11} and B = {2, 3, 5, 10}

Find A∩ B

Ex. Let A = {a, c, e} and B = {b, d, f}

Find A∩ B

The union of two sets A and B is the set of all members that are in either set A
or set B or both.

Ex. Let A = {1, 3, 7, 10, 11} and B = {2, 3, 5, 10}

Find A∪ B

Ex. Let A = {a, c, e} and B = {b, d, f}

Find A∪ B

Find A∩ B

**Solving Compound Inequalities**

Ex. Graph the solution set for the inequality:

Ex. Graph the solution set for the inequality:

Ex. and

Ex.

Ex.

Ex.

Ex.

Ex.

Ex.

Summary