1. VARIABLES AND EXPRESSIONS

2. Definitions: Algebra – Is a language of symbols, including variables. Variable - Is a letter or symbol that represents a quantity that can change. Examples: x, y, a, b, μ, Constant – Is a quantity that does not change. Examples: 1, 6, -2, 3.5 Algebraic Expression – Is an expression that contains one or more variables and may include operations. Examples: r - 8, 3x – 4, 5y Evaluate – Is the process of finding the value of an algebraic expression.

3. VARIABLES AND EXPRESSIONS Algebraic ExpressionNOT an Algebraic Expression 150 + y85 - 16 Complete the table.

4. VARIABLES AND EXPRESSIONS EVALUATING ALGEBRAIC EXPRESSIONS Example 1: Evaluate the following expression for the variable’s given value. 16 + b when b = 25 16 + b 16 + 25 41 When b = 25, the expression equals 41. Original expression Substitute the value for x. Evaluate the expression

5. VARIABLES AND EXPRESSIONS EVALUATING ALGEBRAIC EXPRESSIONS Example 2: Evaluate the following expression for the variable’s given value. 3x – 12 when x = 9 3x – 12 3(9) – 12 27 – 12 15 When x = 9, the expression equals 15. Original expression Substitute the value for x. Evaluate the expression completely.

6. VARIABLES AND EXPRESSIONS EVALUATING ALGEBRAIC EXPRESSIONS Evaluate the following expressions for the variables’ given value. 1.) y – 11 when y = 182.) 6g + 2 when g = 10 3.) c ÷11 when c = 444.) 4.) 5z 3 when z = 5

7. VARIABLES AND EXPRESSIONS EVALUATING ALGEBRAIC EXPRESSIONS IN TABLES Example 3: Evaluate each expression to find the missing values in the table. Substitute each value for n to find the output value. Expression n2n - 2 5 6 7

8. VARIABLES AND EXPRESSIONS Try these. Evaluate each expression to find the missing values in the table. 1.)2.) EVALUATING ALGEBRAIC EXPRESSIONS IN TABLES nn+ 3 1 2 3 n4n ÷ 2 10 15 20

9. VARIABLES AND EXPRESSIONS A rectangle is 8 units wide. How many square units does the rectangle cover if it is 7, 6, 8 or 9 units long? Real-Life Application EVALUATING ALGEBRAIC EXPRESSIONS IN TABLES