1. Holt CA Course 1 1-6Writing Algebraic Expressions Mr. Campbell drives at 55 mi/h. Write an algebraic expression for how far he can drive in h hours. Then evaluate the expression for h = 3, and tell what the value of the expression means. Additional Example 2A: Translating Real-World Problems into Algebraic Expressions You need to put equal parts together. This involves multiplication. 55mi/h  h hours = 55(h) miles 55(h) milesWrite the expression. Substitute 3 for h.55(3) miles Multiply.165 Mr. Campbell can drive 165 miles in 3 hours.

2. Holt CA Course 1 1-6Writing Algebraic Expressions On a test, multiple-choice questions are worth 1 point, short-answer questions are worth 2 points, and essay questions are worth 10 points. Write an algebraic expression for Maritza’s total points if she answers m multiple-choice, s short-answer, and e essay questions correctly. Then evaluate the expression for m = 48, s = 8, and e = 3, and tell what the value of the expression means. Additional Example 2B: Translating Real-World Problems into Algebraic Expressions Multiply to put equal parts together. multiple-choice questions: 1m or m short-answer questions: 2sessay questions: 10e

3. Holt CA Course 1 1-6Writing Algebraic Expressions Additional Example 2B Continued Add to put the parts together. Maritza earned 94 points on the test. Total points: 1m + 2s + 10e 1m + 2s + 10eWrite the expression. Substitute 48 for m, 8 for s, and 3 for e. 1(48) + 2(8) + 10(3) Multiply from left to right.48 + 16 + 30 94Add.

4. Holt CA Course 1 1-6Writing Algebraic Expressions You need to put equal parts together. This involves multiplication. 8(h) unitsWrite the expression. Substitute 5 for h.8(5) units Multiply.40 Julie Ann can build 40 units in 5 hours. Check It Out! Example 2A Julie Ann works on an assembly line building computers. She can assemble 8 units an hour. Write an expression for the number of units she can produce in h hours. Then evaluate the expression for h = 5, and tell what the value of the expression means. 8 units/h  h hours = 8h

5. Holt CA Course 1 1-6Writing Algebraic Expressions For lunch, students have 3 choices. A turkey sandwich for $3, a bowl of soup for $2, and a chicken salad for $4. Write an algebraic expression to show how much it costs for s sandwiches, b bowls of soup, and c chicken salads. Then evaluate the expression for s = 32, b = 20, and c = 10, and tell what the value of the expression means. Check It Out! Example 2B Multiply to put equal parts together. turkey sandwich: 3s bowls of soup: 2bchicken salad: 4c

6. Holt CA Course 1 1-6Writing Algebraic Expressions Check It Out! Example 2B Continued Add to put equal parts together. The cost of 32 turkey sandwiches, 20 bowls of soup, and 10 chicken salads is $176. Total cost: 3s + 2b + 4c 3s + 2b + 4cWrite the expression. Substitute 32 for s, 20 for b, and 10 for c. 3(32) + 2(20) + 4(10) Multiply from left to right.96 + 40 + 40 176Add.

7. Holt CA Course 1 1-6Writing Algebraic Expressions Lesson Quiz Write each phrase as an algebraic expression. 1. 18 less than a number 2. the quotient of a number and 21 3. 8 times the sum of x and 15 4. 7 less than the product of a number and 5 x – 18 8(x + 15) 5n – 7 5. The county fair charges an admission of $6 and then charges $2 for each ride. Write an algebraic expression to represent the total cost after r rides at the fair. 6 + 2r x 21