40. Groceries At your grocery store, milk normally costs $3.60 per gallon. Ground beef costs $3 per pound. Today there are specials: Milk is discounted $.50 per gallon, and ground beef is 20% off. You want to spend no more than $20. Write and graph a linear inequality to show how many gallons of milk and how many pounds of ground beef you can buy today.
41. Reasoning You are graphing a linear inequality of the form y > m x + b . y greater than m x plus b .  The point (1, 2) is not a solution, but (3, 2) is. Is the slope of the boundary line positive, negative, zero, or undefined? Explain.

Standardized Test Prep

SAT/ACT

42. What is the equation of the graph shown?

    

    1. y + x ≥ − 3 y plus x greater than or equal to negative 3
    2. y − x ≥ 3 y minus x greater than or equal to 3
    3. x − y > − 3 x minus y greater than negative 3
    4. y > − x > + 3 y greater than negative x greater than plus 3

43. You secure pictures to your scrapbook using 3 stickers. You started with 24 stickers. There are now 2 pictures in your scrapbook. You write the equation 3(x + 2) = 24 to find the number x of additional pictures you can put in your scrapbook. How many more pictures can you add?

    6. 4
    7. 6
    8. 8
    9. 12

Short Response

44. At Market A, 1-lb packages of rice are sold for the price shown. At Market B, rice is sold in bulk for the price shown. For each market, write a function describing the cost of buying rice in terms of the weight. How are the domains of the two functions different?

    

Mixed Review

See Lesson 6-4.

45. Small Business An electrician spends $12,000 on initial costs to start a new business. He estimates his expenses at $25 per day. He expects to earn $150 per day. If his estimates are correct, after how many working days will he break even?

    See Lesson 3-6.

46. What compound inequality represents the phrase “all real numbers that are greater than 2 and less than or equal to 7”? Graph the solutions.

Get Ready! To prepare for Lesson 6-6, do Exercises 47–49.

See Lesson 6-1.

Solve each system by graphing. Tell whether the system has one solution, infinitely many solutions, or no solution.

47. y = 3 2 x − 2 x + y = 3 table with 2 rows and 1 column , row1 column 1 , y equals , 3 halves , x , row2 column 1 , negative 2 x plus y equals 3 , end table
48. 3 x + y = 6 2 x − y = 4 table with 2 rows and 1 column , row1 column 1 , 3 x plus y equals 6 , row2 column 1 , 2 x minus y equals 4 , end table
49. x + y = 11 x + y = 16 table with 2 rows and 1 column , row1 column 1 , x plus y equals 11 , row2 column 1 , x plus y equals 16 , end table

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