1 / 18

2-7

2-7. Variables and Algebraic Expressions. Course 2. Warm Up. Problem of the Day. Lesson Presentation. 2-7. Variables and Algebraic Expressions. Course 2. Warm Up Evaluate. 1. 5(7) – 1 2. 7(18 – 11) 3. 22 + 17  8 + 3 4. 36 + 15(40 – 35) 5. 3 3 + 7(12 – 4). 34. 49. 161. 111.

bette
Download Presentation

2-7

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. 2-7 Variables and Algebraic Expressions Course 2 Warm Up Problem of the Day Lesson Presentation

  2. 2-7 Variables and Algebraic Expressions Course 2 Warm Up Evaluate. 1.5(7) – 1 2. 7(18 – 11) 3. 22 + 17  8 + 3 4. 36 + 15(40 – 35) 5. 33 + 7(12 – 4) 34 49 161 111 83

  3. 2-7 Variables and Algebraic Expressions Course 2 Problem of the Day How much will it cost to cut a log into eight pieces if cutting it into four pieces costs $12? $28

  4. 2-7 Variables and Algebraic Expressions Course 2 Learn to evaluate algebraic expressions.

  5. 2-7 Variables and Algebraic Expressions Course 2 Insert Lesson Title Here Vocabulary variable constant algebraic expression evaluate

  6. 2-7 Variables and Algebraic Expressions Course 2 Ron Howard was born in 1954. You can find out what year Ron turned 16 by adding the year he was born to his age. 1954 + 16 In algebra, letters are often used to represent numbers. You can use a letter such as a to represent Ron Howard’s age. When he turns a years old, the year will be 1954 + a.

  7. 2-7 Variables and Algebraic Expressions Course 2 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, 1954 + a is an algebraic expression for the year Ron Howard turns a certain age.

  8. 2-7 Variables and Algebraic Expressions Course 2 To evaluate an algebraic expression, substitute a number for the variable.

  9. 2-7 Variables and Algebraic Expressions Course 2 Additional Example 1: Evaluating Algebraic Expressions Evaluate k + 9 for each value of k. k + 9 A. k = 5 Substitute 5 for k. 5 + 9 Add. 14 k + 9 B. k = 2 2 + 9 Substitute 2 for k. 11 Add.

  10. 2-7 Variables and Algebraic Expressions Course 2 Insert Lesson Title Here Try This: Example 1 Evaluate a + 6 for each value of a. a + 6 A. a = 3 Substitute 3 for a. 3 + 6 Add. 9 a + 6 B. a = 5 5 + 6 Substitute 5 for a. 11 Add.

  11. 2-7 Variables and Algebraic Expressions Course 2 Multiplication and division of variables can be written in several ways, as shown in the table. q 2 q/2 7t 7 · t 7(t) 7  t q ÷ 2 s r ab a · b s/r a(b) a  b s ÷ r When evaluating expressions, use the order of operations.

  12. 2-7 Variables and Algebraic Expressions Course 2 Additional Example 2A: Evaluating Algebraic Expressions Involving Order of Operations Evaluate the expression for the given value of the variable. A. 4x – 3 for x = 2 4(2) – 3 Substitute 2 for x. Multiply. 8 – 3 Subtract. 5

  13. 2-7 Variables and Algebraic Expressions Course 2 Additional Example 2B & 2C: Evaluating Algebraic Expressions Involving Order of Operations B. s ÷ 5 + s, for s = 15 Substitute 15 for s. 15 ÷ 5 + 15 3 + 15 Divide. 18 Add. C. 5x2 + 3x, for x = 2 5(2)2 + 3(2) Substitute 2 for x. 5(4) + 3(2) Evaluate the power. Multiply. 20 + 6 26 Add.

  14. 2-7 Variables and Algebraic Expressions Course 2 Insert Lesson Title Here Try This: Example 2A Evaluate each expression for the given value of the variable. A. 3x – 2 for x = 3 3(3) – 2 Substitute 3 for x. Multiply. 9 – 2 Subtract. 7

  15. 2-7 Variables and Algebraic Expressions Course 2 Insert Lesson Title Here Try This: Example 2B & 2C B. r ÷ 3 + r, for r = 12 Substitute 12 for r. 12 ÷ 3 + 12 4 + 12 Divide. 16 Add. C. 4y2 + 2y, for y = 3 4(3)2 + 2(3) Substitute 3 for y. 4(9) + 2(3) Evaluate the power. Multiply. 36 + 6 42 Add.

  16. 2-7 Variables and Algebraic Expressions Course 2 Additional Example 3: Evaluating Algebraic Expressions with Two Variables 6 a Evaluate + 4b, for a = 3 and b = 2. 6 a + 4b 6 3 Substitute 3 for a and 2 for b. + 4(2) Divide and multiply from left to right. 2 + 8 10 Add.

  17. 2-7 Variables and Algebraic Expressions Course 2 Insert Lesson Title Here Try This: Example 3 8 w Evaluate + 2x, for w = 4 and x = 2. 8 w + 2x 8 4 + 2(2) Substitute 4 for w and 2 for x. Divide and multiply from left to right. 2 + 4 6 Add.

  18. 2-7 Variables and Algebraic Expressions Course 2 Insert Lesson Title Here Lesson Quiz Evaluate n + 7 for each value of n. 1.n = 25 2.n =31 Evaluate each algebraic expression for the given value of the variables 3. 6y – 5 for y = 7 4. 4x2 + 3x for x = 6 5. + 3y for x = 4 and y = 3 6. The expression 7d gives the number of days in d weeks. Evaluate 7d for d = 12. How many days are in 12 weeks? 32 38 37 162 56 x 23 84

More Related