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

1-2 Writing Algebraic Expressions Learn to translate between algebraic expressions and word phrases.

1-2 Writing Algebraic Expressions a number plus 5 add 5 to a number sum of a number and 5 5 more than a number a number increased by 5 a number minus 11 subtract 11 from a number difference of a number and less than a number a number decreased by 11 3 times a number 3 multiplied by a number product of 3 and a number a number divided by 7 7 divided into a number quotient of a number and 7 + –   Word Phrases Expression n + 5 x – 11 3m3m or a  7 a 7

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

1-2 Writing Algebraic Expressions Write an algebraic expression for each word phrase. Check It Out: Example 1 A. the sum of a number h and 88 minus 4 the sum of h and 88 minus 4 h + 88 – 4 B. the quotient of a number f and 6 quotient of f and 6 f  6 f 6

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

1-2 Writing Algebraic Expressions Check It Out: Example 2 Write a word phrase for the algebraic expression b b 7 plus the product of 19 and b 7 plus the product of 19 and b.

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.

1-2 Writing Algebraic Expressions A restaurant leased its banquet hall for a function. The cost was $10 per person. Write an algebraic expression to evaluate what the cost would be if 20, 21, 22, or 23 people attended the function. Additional Example 3: Writing and Evaluating Expressions in Word Problems $10 dollars nCombine n equal amounts of $10. $10nIn dollars 20 $10 20 $ $10 21 $ $10 22 $ $10 23 $230 n $10 n Cost Evaluate for n = 20, 21, 22, and 23.

1-2 Writing Algebraic Expressions Gasoline costs $3.59 per n gallons. What will the cost be for 10, 12, 14, and 15 gallons? Check It Out: Example 3 $3.59 nCombine n equal amounts of $3.59. $3.59nIn dollars 10 $ $ $ $ $ $ $ $53.85 n $3.59 n Cost Evaluate for n = 10, 12, 14, and 15.

1-2 Writing Algebraic Expressions Write a word problem that can be evaluated by the algebraic expression 27 + t, and evaluate the expression for t = Additional Example 4: Writing a Word Problem from a Math Expression 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 = Substitute 1.76 for t. The total cost of the sweater was $28.76.

1-2 Writing Algebraic Expressions Write a word problem that can be evaluated by the algebraic expression 43 – d, and evaluate the expression for d = Check It Out: Example 4 Possible Answer: Tina bought a new jacket for $43 minus a store credit. If the store credit was $10.24, what was the total cost of the jacket? 43 – d 43 – = Substitute for t. The total cost of the jacket was $32.76.

1-2 Writing Algebraic Expressions Lesson Quizzes Lesson Quiz for Student Response Systems

1-2 Writing Algebraic Expressions 1. Identify the algebraic expression for the given word phrase. 20 less than a number r A. 20 – r B. r – 20 C. 20r – r D. 20 – 20r Lesson Quiz for Student Response Systems

1-2 Writing Algebraic Expressions 2. Identify the algebraic expression for the given word phrase. a number p divided by 16 A. C. B. D. Lesson Quiz for Student Response Systems p p 16p p p 16p

1-2 Writing Algebraic Expressions 3. Identify the algebraic expression for the given word phrase. 6 times the sum of r and 9 A. 6 + r + 9 B. 6r + 9 C. r(6 + 9) D. 6(r + 9) Lesson Quiz for Student Response Systems

1-2 Writing Algebraic Expressions 4. Identify the algebraic expression that evaluates the given word problem. Alice buys x apples for $0.75 each. If she buys 24 of them, how much will they cost? A. 0.75x; $9 B. 24x; $9 C. 0.75x; $18 D. 24x; $18 Lesson Quiz for Student Response Systems