1. Evaluating Expressions and Properties

2. Evaluate expressions containing exponents. Objective

3. A power is an expression written with an exponent and a base or the value of such an expression. 3² is an example of a power. The base is the number that is used as a factor. The exponent, 2 tells how many times the base, 3, is used as a factor. 3 2

4. There are no easy geometric models for numbers raised to exponents greater than 3, but you can still write them using repeated multiplication or a base and exponent. 3 to the second power, or 3 squared 3  3  3  3  3 Multiplication Power Value Words 3  3  3  3 3  3  3 3  3 3 3 to the first power 3 to the third power, or 3 cubed 3 to the fourth power 3 to the fifth power 3 9 27 81 243 3 1 Reading Exponents 3 2 3 3 3 4 3 5

5. Caution! In the expression –5 2 , 5 is the base because the negative sign is not in parentheses. In the expression (–2), –2 is the base because of the parentheses.

6. Evaluate each expression. A. (–6) 3 (–6)(–6)(–6) – 216 B. –10 2 – 1 • 10 • 10 – 100 Use –6 as a factor 3 times. Find the product of –1 and two 10’s. Example 2: Evaluating Powers Think of a negative sign in front of a power as multiplying by a –1.

7. Evaluate each expression. a. (–5) 3 b. –6 2 Check It Out! Example 2 (–5)(–5)(–5) Use –5 as a factor 3 times. – 125 – 1  6  6 – 36 Think of a negative sign in front of a power as multiplying by –1. Find the product of –1 and two 6’s.

8. Use the order of operations to simplify expressions. Objective

9. When a numerical or algebraic expression contains more than one operation symbol, the order of operations tells which operation to perform first. First: Second: Third: Fourth: Perform operations inside grouping symbols. Evaluate powers. Perform multiplication and division from left to right. Perform addition and subtraction from left to right. Order of Operations

10. Grouping symbols include parentheses ( ), brackets [ ], and braces { }. If an expression contains more than one set of grouping symbols, evaluate the expression from the innermost set first.

11. Helpful Hint The first letter of these words can help you remember the order of operations. P lease E xcuse M y D ear A unt S ally P arentheses E xponents M ultiply D ivide A dd S ubtract

12. Simplify each expression. A. 15 – 2 · 3 + 1 15 – 2 · 3 + 1 15 – 6 + 1 10 There are no grouping symbols. Multiply. Subtract and add from left to right. B. 12 – 3 2 + 10 ÷ 2 12 – 3 2 + 10 ÷ 2 12 – 9 + 10 ÷ 2 12 – 9 + 5 8 There are no grouping symbols. Evaluate powers. The exponent applies only to the 3. Divide. Subtract and add from left to right. Example 1: Translating from Algebra to Words

13. 5.4 – 3 2 + 6.2 5.4 – 3 2 + 6.2 There are no grouping symbols. 5.4 – 9 + 6.2 Simplify powers. – 3.6 + 6.2 2.6 Subtract Add. Check It Out! Example 1b Simplify the expression.

14. Example 2A: Evaluating Algebraic Expressions Evaluate the expression for the given value of x. 10 – x · 6 for x = 3 10 – x · 6 10 – 3 · 6 10 – 18 – 8 First substitute 3 for x. Multiply. Subtract.

15. Evaluate the expression for the given value of x. 4 2 ( x + 3) for x = –2 4 2 ( x + 3) 4 2 ( –2 + 3) 4 2 ( 1 ) 16 (1) 16 First substitute –2 for x. Perform the operation inside the parentheses. Evaluate powers. Multiply. Example 2B: Evaluating Algebraic Expressions

16. Fraction bars, radical symbols, and absolute-value symbols can also be used as grouping symbols. Remember that a fraction bar indicates division.

17. Check It Out! Example 3a Simplify. 5 + 2(–8) (–2) – 3 3 1 The fraction bar acts as a grouping symbol. Simplify the numerator and the denominator before dividing. Evaluate the power in the denominator. Multiply to simplify the numerator. Add. Divide. 5 + 2(–8) – 8 – 3 5 + 2(–8) (–2) – 3 3 5 + ( –16 ) – 8 – 3 – 11 – 11

18. Identify the Commutative, Associative, and Distributive Properties to simplify expressions. Objectives

20. The Distributive Property is used with Addition to Simplify Expressions. The Distributive Property also works with subtraction because subtraction is the same as adding the opposite.