1. 1-1 Variables and Expressions Course 3 Warm Up Warm Up Problem of the Day Problem of the Day Lesson Presentation Lesson Presentation

2. Warm Up Evaluate. 1. 21  2(3) 15 31 21 20.4 15.3 Course 3 1-1 Variables and Expressions 5. 7(2.9)  5 4. 6(1.4) + 12 3. 2(9) + (3) 2. 4 + 3  9

3. Problem of the Day Miss Smith obtained the prices below from the landscape company. She plans to buy five birch, two elm, one dogwood, and two oak trees. The landscape company will charge her $15 to plant each tree. How much will it cost? Trees Price Maple Elm Oak Dogwood Crab apple Birch $16.99 $22.99 $19.99 $23.99 $26.99 $17.99 $337.90 Course 3 1-1 Variables and Expressions

4. Learn to evaluate algebraic expressions. Course 3 1-1 Variables and Expressions

5. Vocabulary variable coefficient algebraic expression constant evaluate substitute Course 3 1-1 Variables and Expressions

6. A variable is a letter that represents a value that can change or vary. The coefficient is the number multiplied by the variable. CoefficientVariable Course 3 1-1 Variables and Expressions

7. Course 3 1-1 Variables and Expressions Order of Operations PEMDAS: 1. Parentheses 2. Exponents 3. Multiply and Divide from left to right. 4. Add and Subtract from left to right. Remember!

8. Evaluate each expression for the given value of the variable. Additional Example 1A: Evaluating Algebraic Expressions with One Variable Substitute 12 for x. Subtract. x – 5 for x = 12 12 – 5 Course 3 1-1 Variables and Expressions 7

9. Evaluate each expression for the given value of the variable. Additional Example 1B: Evaluating Algebraic Expressions with One Variable Course 3 1-1 Variables and Expressions Substitute 4 for y. Multiply. 2y + 1 for y = 4 2(4) + 1 8 + 1 Add. 9

10. Evaluate each expression for the given value of the variable. Check It Out: Examples 1 Substitute 3 for x. Add. A. x + 5 for x = 3 3 + 5 Course 3 1-1 Variables and Expressions 8 Substitute 11 for c. Multiply. B. 4c + 1 for c = 11 4(11) + 1 44 + 1 Add. 45

11. Evaluate each expression for the given values of the variables. Additional Example 2: Evaluating Algebraic Expressions with Two Variables Substitute 2 for x and 1 for y. Multiply. A. 4x + 3y for x = 2 and y = 1 4(2) + 3(1) Course 3 1-1 Variables and Expressions 8 + 3 Substitute 3 for r and 5 for p. Multiply. B. 9r – 2p for r = 3 and p = 5 9(3) – 2(5) 27 – 10 Add. 11 Subtract. 17

12. Evaluate each expression for the given values of the variables. Check It Out: Example 2 Substitute 3 for x and 4 for y. Multiply. A. 3x + 2y for x = 3 and y = 4 3(3) + 2(4) Course 3 1-1 Variables and Expressions 9 + 8 Substitute 2 for q and 2 for r. Multiply. B. 8q – 3r for q = 2 and r = 2 8(2) – 3(2) 16 – 6 Add. 17 Subtract. 10

13. Use the expression 1.8c + 32 to convert the boiling point temperature from degrees Celsius to degrees Fahrenheit. Additional Example 3A: Physical Science Application Course 3 1-1 Variables and Expressions Substitute 100 for c. Multiply. Boiling point of water at sea level: 100°C 1.8(100) + 32 180 + 32 1.8c + 32 Add. 212 100°C = 212°F Water boils at 212°F.

14. Lesson Quiz Evaluate each expression for the given values of the variables. 1.6x + 9 for x = 3 2.4x + 3y for x = 2, y = 3 3.If n is the amount of money in a savings account, then the expression n + 0.03n can be used to find the amount in the account after it has earned interest for one year. Find the total in the account after one year if $500 is the initial amount. 27 17 $515 Course 3 1-1 Variables and Expressions