Algebraic Expressions Unit 6 Evaluating Algebraic Expressions Vocabulary

Algebraic Expressions

Unit 6 – Evaluating Algebraic Expressions

Vocabulary Evaluate – to find the value of a mathematical expression. Substitute – to replace variables in a given expression or equation with designated values in order to evaluate the expression

Evaluating Algebraic Expressions Example Evaluate each expression for the given value of the variable. z – 13 when z = 20 3 m + 2 when m = 5 Yes, you have to rewrite the expression z – 13 (20) – 13 7 Yes, you have to use parenthesis 3 m + 2 3(5) + 2 15 + 2 17

Evaluating Algebraic Expressions Example Evaluate each expression for the given value of the variable. 40 – 5 p when p = 6 40 – 5 p 40 – 5(6) 40 – 30 10 •

Evaluating Algebraic Expression Practice Evaluate each of the following algebraic expression 1. x + 12 when x = 5 17 2. 16 – y when y = 9 7 •

Evaluating Algebraic Expressions Example Write each verbal expression as a variable expression and then evaluate each of the following when x = 3 The sum of 6 x and 4 12 less than 7 x 6 x + 4 7 x - 12 6(3) + 4 7(3) – 12 18 + 4 21 – 12 22 9

Evaluating Algebraic Expressions Example Write each verbal expression as a variable expression and then evaluate each of the following when x = 3 The product of (5 + 3 x) and (2 x – 3) (5 + 3(3)) × (2(3) – 3) (5 + 9) × (6 – 3) 14 × 3 42

Evaluating Algebraic Expression Practice Write an algebraic expression for each of the following verbal expressions. Then use the value of the variable to evaluate the expression. 1. A number that is 5 more than twice x when x = 2 2 x + 5 9 2. The total cost of 4 pencils and 5 pens if each pencil costs w cents and each pen costs 2 w cents when w = $0. 25 4 w + 5(2 w) $3. 50