Chapter 3

3.5: Compound Inequalities

Definition Two inequalities that are joined by the word

‘and’ or ‘or’ form a compound inequality. This is for when we want x to be between two

numbers or not between two numbers.

Writing a Compound Inequality All real numbers that are at least -2 and at

most 4

Today’s temp. will be above 32° but below 40°

Writing a Compound Inequality The books were priced from $3.50 to $9.00

All real numbers less than -3 and greater than 7

Discounted fairs are available to children 12 and under and adults at least 60 years old.

Solving Compound Inequalities -4 ≤ r – 5 ≤ -1

-6 ≤ 3x ≤ 15

Solving Compound Inequalities 4v + 3 < -5 or -2v + 7 < 7

-2x + 7 > 3 or 3x – 4 ≥ 5

Word Problem The acidity of the water in a swimming pool is

considered normal if the average of 3 pH readings is between 7.2 and 7.8, inclusive. The first 2 readings are 7.4 and 7.9. What are the possible values for the 3rd pH reading?

Assignment p. 163-164

2-32, 44 evens