1 2 Writing Algebraic Expressions Essential Question How

1 -2 Writing Algebraic Expressions Essential Question How do verbal expressions translate to algebraic expressions? Holt CA Course 2

1 -2 Writing Algebraic Expressions Warm Up Evaluate each expression for the given values of the variables. 1. 9 y – 13 for y = 4 23 2. 6 n + 2 p for n = 2 and p = 3 18 3. 3 x – y for x = 1 and y = 2 1 Which operation symbol goes with each word? 4. Sum + 6. Quotient Holt CA Course 2 5. Product 7. Difference

1 -2 Writing Algebraic Expressions Word Phrases + – • • Expression a number plus 5 sum of a number and 5 5 more than a number subtract 11 from a number • difference of a number and 11 n+5 x – 11 • 11 less than a number • 3 multiplied by a number • product of 3 and a number • 7 divided into a number • quotient of a number and 7 Holt CA Course 2 3 m or 3 m a or a 7 7

1 -2 Writing Algebraic Expressions Additional Example 1: Translating Word Phrases into Math Expressions Write an algebraic expression for each word phrase. A. 9 less than a number w w – 9 w– 9 B. 3 increased by the difference of p and 5 3 + (p – 5) Holt CA Course 2

1 -2 Writing Algebraic Expressions Check It Out! Example 1 Write an algebraic expression for each word phrase. A. 88 times the difference of h and 4 88 • (h – 4) 88(h – 4) B. the quotient of a number f and 6 quotient of f and 6 f 6 Holt CA Course 2

1 -2 Writing Algebraic Expressions Additional Example 2: Translating Math Expressions into Word Phrases Write a word phrase for the algebraic expression 9 – 3 c 9 – 3 9 minus • c the product of 3 and c 9 minus the product of 3 and c Holt CA Course 2

1 -2 Writing Algebraic Expressions Check It Out! Example 2 Write a word phrase for the algebraic expression 7 + 19 b 7 + 19 7 plus • b the product of 19 and b 7 plus the product of 19 and b Holt CA Course 2

1 -2 Writing Algebraic Expressions To solve a word problem, first interpret the action you need to perform and then choose the correct operation for that action. Holt CA Course 2

1 -2 Writing Algebraic Expressions Additional Example 3: Writing and Evaluating Expressions in Word Problems A restaurant leased its banquet hall for a function. The cost was $10 person. Write an algebraic expression to determine what the cost would be if n people attended the function. Then evaluate the expression for 20, 21, 22, or 23 people. $10 • n 10 n n 20 21 22 23 Holt CA Course 2 Combine n equal amounts of $10. Cost in dollars 10 n 10(20) 10(21) 10(22) 10(23) Cost $200 $210 $220 $230 Evaluate for n = 20, 21, 22, and 23.

1 -2 Writing Algebraic Expressions Check It Out! Example 3 Gasoline costs $1. 99 per n gallons. What will the cost be for 10, 12, 14, and 15 gallons? $1. 99 • n 1. 99 n Combine n equal amounts of $1. 99. Cost in dollars n 1. 99 n Cost 10 12 14 15 1. 99(10) 1. 99(12) 1. 99(14) 1. 99(15) $19. 90 $23. 88 $27. 86 $29. 85 Holt CA Course 2 Evaluate for n = 10, 12, 14, and 15.

1 -2 Writing Algebraic Expressions Additional Example 4: Writing a Word Problem from a Math Expression Write a word problem that can be evaluated by the algebraic expression 27 + t, and evaluate the expression for t = 1. 76. Possible answer: Amed bought a new sweater for $27 plus sales tax t. If the tax was $1. 76, what was the total cost of the sweater? 27 + t 27 + 1. 76 = 28. 76 Substitute 1. 76 for t. The total cost of the sweater was $28. 76. Holt CA Course 2

1 -2 Writing Algebraic Expressions Check It Out! Example 4 Write a word problem that can be evaluated by the algebraic expression 43 – d, and evaluate the expression for d = 10. 24. Possible answer: Tina bought a new jacket for $43 minus a store credit. If the store credit was $10. 24, what did Tina pay for the jacket? 43 – d 43 – 10. 24 = 32. 76 Substitute 10. 24 for d. Tina paid $32. 76 for the jacket. Holt CA Course 2