1 2 Writing Algebraic Expressions Warm Up Evaluate

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 + 5. Product 6. Quotient 7. Difference –

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

1 -2 Writing Algebraic Expressions Word Phrases + – • • • a number plus 5 add 5 to a number sum of a number and 5 5 more than a number increased by 5 a number minus 11 subtract 11 from a number difference of a number and 11 11 less than 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 Expression n+5 x – 11 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) 3+p– 5

1 -2 Writing Algebraic Expressions Check It Out: Example 1 Write an algebraic expression for each word phrase. 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

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.

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.

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 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 evaluate what the cost would be if 20, 21, 22, or 23 people attended the function. $10 dollars • n $10 n n 20 21 22 23 $10 $10 $10 • • • n 20 21 22 23 Combine n equal amounts of $10. In dollars 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 $3. 59 per n gallons. What will the cost be for 10, 12, 14, and 15 gallons? $3. 59 • n $3. 59 n n 10 12 14 15 Combine n equal amounts of $3. 59. In dollars $3. 59 • n $3. 59 • 10 $3. 59 • 12 $3. 59 • 14 $3. 59 • 15 Cost $35. 90 $43. 08 $50. 26 $53. 85 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.

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 was the total cost of the jacket? 43 – d 43 – 10. 24 = 32. 76 Substitute 10. 24 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 Lesson Quiz for Student Response Systems 1. Identify the algebraic expression for the given word phrase. 20 less than a number r A. 20 – r B. r – 20 C. 20 r – r D. 20 – 20 r

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

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

1 -2 Writing Algebraic Expressions Lesson Quiz for Student Response Systems 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. 75 x; $9 B. 24 x; $9 C. 0. 75 x; $18 D. 24 x; $18