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Math 7A: Monday, Sept. 12, 2011 Test Alert: Unit 1 Test on Friday! Test Alert: Unit 1 Test on Friday! Homework: Homework: –Holt “Ready to Go On?” p. 90 –POW due Friday. Warm-up: “The Error Detective” Warm-up: “The Error Detective” –Work with a partner to try to determine what errors each person made. –Both people need to write down the answers.

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Math 7A Agenda Essential Question: What models for positive and negative numbers would help in showing the relationships in a problem situation? Essential Question: What models for positive and negative numbers would help in showing the relationships in a problem situation? GPS: M7N1. Students will understand the meaning of positive and negative rational numbers and use them in computation. GPS: M7N1. Students will understand the meaning of positive and negative rational numbers and use them in computation. “Sums & Products” puzzle lesson. “Sums & Products” puzzle lesson.

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Homework: –1-1 Practice B w.s. –POW due Friday. Warm Up Evaluate 2(3) Course (2.9) (1.4) (9) + (3) 9 Math 7: Monday, September 12 Test Alert: Unit 1 Test will be on Wednesday, September 21

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Learn to evaluate algebraic expressions. Course Variables and Expressions Essential Question: What properties and conventions do I need to understand in order to simplify and evaluate algebraic expressions? GPS: M7A1.b: Simplify and evaluate algebraic expressions, using commutative, associative, and distributive properties as appropriate.

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Vocabulary variable coefficient algebraic expression constant evaluate substitute Course Variables and Expressions

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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 Variables and Expressions

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In the algebraic expression x + 6, 6 is a constant because it does not change. To evaluate an algebraic expression, substitute a given number for the variable, and find the value of the resulting numerical expression. Course Variables and Expressions An algebraic expression has one or more variables.

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

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Course 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!

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

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Evaluate the expression for the given values of the variable. Additional Example 1C: Evaluating Algebraic Expressions with One Variable 6(n + 2) – 4 for n = 5, 6, 7 Course Variables and Expressions n Substitute Parentheses Multiply Subtract 6(5 + 2) – 46(7) – 4 42 – (6 + 2) – 46(8) – 4 48 – (7 + 2) – 46(9) – 4 54 – 4 50

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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 = Course Variables and Expressions 8 Substitute 11 for c. Multiply. B. 4c + 1 for c = 11 4(11) Add. 45

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Evaluate the expression for the given values of the variable. Check It Out: Example 1 C. 5(n + 3) – 2 for n = 3, 4, 5 Course Variables and Expressions n Substitute Parentheses Multiply Subtract 5(3 + 3) – 25(6) – 2 30 – (4 + 3) – 25(7) – 2 35 – (5 + 3) – 25(8) – 2 40 – 2 38

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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 Variables and Expressions 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

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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 Variables and Expressions 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

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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 Variables and Expressions Substitute 100 for c. Multiply. Boiling point of water at sea level: 100°C 1.8(100) c + 32 Add °C = 212°F Water boils at 212°F.

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Additional Example 3B: Physical Science Application Course Variables and Expressions Substitute 85 for c. Multiply. Boiling point of water at an altitude of 4400 t meters: 85°C 1.8(85) c + 32 Add °C = 185°F Water boils at 185°F at 4400 m.

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Convert the temperature from degrees Celsius to degrees Fahrenheit. Check It Out: Example 3A Course Variables and Expressions Substitute 50 for c. Multiply. Europe’s highest recorded temperature (Seville, Spain): 50°C 1.8(50) c + 32 Add °C = 122°F The highest recorded temperature in Europe is 122°F.

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Use the expression 1.8c + 32 to convert each boiling point temperature from degrees Celsius to degrees Fahrenheit. Check It Out: Example 3B Course Variables and Expressions Substitute 10 for c. Multiply. 10°C 1.8(10) c + 32 Add °C = 50°F

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Lesson Quiz Evaluate each expression for the given values of the variables. 1. 6x + 9 for x = 3 2. x + 14 for x = x + 3y for x = 2, y = x – 2.9y for x = 19, y = 6 5. If n is the amount of money in a savings account, then the expression n n 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 $515 Course Variables and Expressions

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Course Variables and Expressions Assignment: P. 8 (11-47 odd) 1-1 Practice A w.s.

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