1. 7.4 HW Answers

2. 1. 2. 3. 4. 5. (4, -1) (5, 3) (-½, -2) (9, -3) (-10, -5) 6. 7. 8. 9. 10. (19, 16) (5, 6) (-7, -12) (2, 1) (4, 4)

3. 10x + 2y = 155 12x + 3y = 189 $14.50 balls$5 bags

7. (-2, -2)

8. 5(y + 9) – 3y = 7 y = -19 x = -19 + 9 x = -10 (-10, -19)

9. -1/5 0 13/5

10. -11 0 5

11. Scoring Your Homework Count how many problems you missed or didn’t do 0-1 missed = 10 2-3 missed = 9 4-5 missed = 8 6-7 missed = 7 8-9 missed = 6 10-11 missed = 5 12-13 missed = 4 14-15 missed = 3 16-17 missed = 2 18-19 missed = 1 20-21 missed = 0

12. Table of Contents Topic Page #... 7.1 Solve Systems By Graphing 76 7.2 Solve Systems By Substitution 77 7.3 Solve Systems By Combination 78 7.4 Multiplication w/ Combination 79 7.5 System Word Problems 80

13. 1.You are selling tickets to a play. The price of a student ticket is $5, and the price of an adult ticket is $8. You sell 556 tickets and you collect $3,797. How many adult and student tickets did you sell? Step 1: Choose your variables S = student ticket a = adult ticket

14. 1.You are selling tickets to a play. The price of a student ticket is $5, and the price of an adult ticket is $8. You sell 556 tickets and you collect $3,797. How many adult and student tickets did you sell? Step 2: Write two equations: A) One that represents the value of the items 5s + 8a = 3797 B) One that represent the quantity of items s + a = 556

15. Step 3: Solve the system using substitution or elimination 5s + 8a = 3797 s + a = 556 (–8) 5s + 8a = 3797 -8s – 8a = -4448 + s = 217 -3s = -651 217 + a = 556 a = 339

16. 2. A bag contains dimes and nickels. There are 18 coins in the bag. The value of the coins is $1.25. How many of each type of coin is in the bag? Step 1: Choose your variables d = # dimes n = # nickels

17. 2. A bag contains dimes and nickels. There are 18 coins in the bag. The value of the coins is $1.25. How many of each type of coin is in the bag? Step 2: Write two equations: A) One that represents the value of the items 0.10d + 0.05n = 1.25 B) One that represent the quantity of items d + n = 18

18. Step 3: Solve the system using substitution or elimination 0.10d + 0.05n = 1.25 d + n = 18 (–5) 10d + 5n = 125 -5d – 5n = -90 + d = 7 5d = 35 7 + n = 18 n = 11 (100)

19. 3. Kylie has 4.50 in dimes and quarters. She has 3 more dimes than quarters. How many quarters does she have? d = # dimes q = # quarters 0.10d + 0.25q = 4.50 d = q + 3 0.10(q + 3) + 0.25q = 4.50 0.10q + 0.30 + 0.25q = 4.50 0.35q + 0.30 = 4.50 0.35q = 4.20 q = 12 = 12 + 3 = 15

20. 4. An adult ticket to a school play costs $5 and a student ticket costs $3. A total of $460 was collected from the sale of 120 tickets. How many student tickets were purchased? a = adult ticket s = student ticket 5a + 3s = 460 a + s = 120

21. 5a + 3s = 460 a + s = 120 (–3) 5a + 3s = 460 -3a – 3s = -360 + a = 50 2a = 100 50 + s = 120 s = 70

22. 5. A drummer goes to Guitar Center and buys drum sticks and brushes. The wood sticks that he buys are $10.50 a pair, and the brushes are $24 a pair. He buys twice as many pairs of wood sticks as brushes, and ends up spending a total of $90. How many pair of sticks and brushes did he buy? d = drum sticks b = brushes 10.50d + 24b = 90 d = 2b

23. 10.50d + 24b = 90 d = 2b 10.50(2b) + 24b = 90 21b + 24b = 90 45b = 90 b = 2 = 2(2) = 4

24. 6. The sophomore class is selling pretzels and popcorn at a school event to raise money for a dance. They charge $2.50 for a bag of popcorn and $2 for a pretzel. They collect $336 during the event. They sell twice as many bags of popcorn as pretzels. How many pretzels do they sell? z = pretzels p = popcorn 2.50p + 2z = 336 p = 2z

25. 2.50p + 2z = 336 p = 2z 2.50(2z) + 2z = 336 5z + 2z = 336 7z = 336 z = 48 = 2(48) = 96

26. 7. You went to Home Depot and bought two types of plants. One type was a flowering plant while the other was non-flowering. The flowering plant cost $3.20 each and the non-flowering plant cost $1.50 each. You purchased a total of 24 plants for $49.60. How many of each type of plant did he buy? f = flower plant n = non-flower 3.20f + 1.5n = 49.60 f + n = 24

27. 3.20f + 1.5n = 49.60 f + n = 24 (–15) 32f + 15n = 496 -15f – 15n = -360 + f = 8 17f = 136 8 + n = 24 n = 16 (10)