1. 1-6 Variables and Algebraic Expressions Warm Up Evaluate. 1. 5(7) – 1 2. 7(18 – 11) 3. 22 + 16  8 + 3 4. 36 + 15(40 – 35) 5. 3 3 + 7(12 – 4) 34 49 27 111 83

2. 1-6 Variables and Algebraic Expressions Learning Target 3 I can evaluate an algebraic expression.

3. 1-6 Variables and Algebraic Expressions Vocabulary variable constant coefficient algebraic expression evaluate substitute

4. 1-6 Variables and Algebraic Expressions Harrison Ford was born in 1942. You can find out what year Harrison turned 18 by adding the year he was born to his age. 1942 + 18 In algebra, letters are often used to represent numbers. You can use a letter such as a to represent Harrison Ford’s age. When he turns a years old, the year will be 1942 + a.

5. 1-6 Variables and Algebraic Expressions The letter a has a value that can change, or vary. When a letter represents a number that can vary, it is called a variable. The year 1954 is a constant because the number cannot change. An algebraic expression consists of one or more variables. It usually contains constants and operations. For example, 1942 + a is an algebraic expression for the year Ron Howard turns a certain age.

6. 1-6 Variables and Algebraic Expressions Examples: write an algebraic expression for each word phrase: 1) The product of 5 and a number. 2) The sum of a number and 10 3) 3 less than twice a number 4) 5 less than a number

7. 1-6 Variables and Algebraic Expressions To evaluate an algebraic expression, substitute a number for the variable. AgeYear born + age = year at age 161954 + 161970 181954 + 181972 211954 + 211975 361954 + 361990 a1954 + a

8. 1-6 Variables and Algebraic Expressions Evaluate k + 9 for each value of k. Additional Example 1: Evaluating Algebraic Expressions A. k = 5 k + 9 5 + 9 14 Substitute 5 for k. Add. B. k = 2 k + 9 2 + 9Substitute 2 for k. 11 Add.

9. 1-6 Variables and Algebraic Expressions Additional Example 2: Evaluating Algebraic Expressions Involving Order of Operations B. s ÷ 5 + s, for s = 15 15 ÷ 5 + 15 3 + 15 18 C. 5x 2 + 3x, for x = 2 5(2) 2 + 3(2) 5(4) + 3(2) 20 + 6 26 Substitute 15 for s. Divide. Add. Substitute 2 for x. Evaluate the power. Multiply. Add.

10. 1-6 Variables and Algebraic Expressions Check It Out: Example 2A Evaluate the expression for the given value of the variable. A. 3x – 2 for x = 3 3(3) – 2 9 – 2 7 Substitute 3 for x. Multiply. Subtract.

11. 1-6 Variables and Algebraic Expressions Check It Out: Example 2 B. r ÷ 3 + r, for r = 12 12 ÷ 3 + 12 4 + 12 16 C. 4y 2 + 2y, for y = 3 4(3) 2 + 2(3) 4(9) + 2(3) 36 + 6 42 Substitute 12 for r. Divide. Add. Substitute 3 for y. Evaluate the power. Multiply. Add.

12. 1-6 Variables and Algebraic Expressions Evaluate Additional Example 3: Evaluating Algebraic Expressions with Two Variables 6a6a + 4b, for a = 3 and b = 2. 6a6a + 4b 6363 + 4(2) 2 + 8 10 Substitute 3 for a and 2 for b. Divide and multiply from left to right. Add.

13. 1-6 Variables and Algebraic Expressions Check It Out: Example 3 Evaluate 8w8w + 2x, for w = 4 and x = 2. 8w8w + 2x 8484 + 2(2) 2 + 4 6 Substitute 4 for w and 2 for x. Divide and multiply from left to right. Add.

14. 1-6 Variables and Algebraic Expressions 1. Evaluate m + 4 for m = 19. A. 21 B. 27 C. 23 D. 28 Lesson Quiz—Have you mastered the target? Put your name on a half sheet of paper. Work the problem and write the letter choice that matches your answer.

15. 1-6 Variables and Algebraic Expressions 2. Evaluate 7x – 8 for x = 5. A. 20 B. 27 C. 22 D. 32 Lesson Quiz for Student Response Systems

16. 1-6 Variables and Algebraic Expressions 3. Evaluate 6x 2 + 5x for x = 5. A. 185 B. 85 C. 175 D. 50 Lesson Quiz for Student Response Systems

17. 1-6 Variables and Algebraic Expressions 4. Evaluate + 5y for x = 3 and y = 5. A. 38 B. 44 C. 54 D. 64 Lesson Quiz for Student Response Systems 39 y

18. 1-6 Variables and Algebraic Expressions 5. The expression 12n gives the number of months in n years. Evaluate 12n for n = 3. How many months are in 3 years? A. 12 months B. 24 months C. 36 months D. 48 months Lesson Quiz for Student Response Systems

19. 1-6 Variables and Algebraic Expressions Homework Do the circled problems on the back of your notes page. Show your substitutions!!! Show the order of operations when necessary.