7.4 HW Answers

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

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

(-2, -2)

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

-1/5 0 13/5

Scoring Your Homework Count how many problems you missed or didn’t do 0-1 missed = missed = missed = missed = missed = missed = missed = missed = missed = missed = missed = 0

Table of Contents Topic Page # Solve Systems By Graphing Solve Systems By Substitution Solve Systems By Combination Multiplication w/ Combination System Word Problems 80

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

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

Step 3: Solve the system using substitution or elimination 5s + 8a = 3797 s + a = 556 (–8) 5s + 8a = s – 8a = s = s = a = 556 a = 339

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

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 n = 1.25 B) One that represent the quantity of items d + n = 18

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

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 q = 4.50 d = q (q + 3) q = q q = q = q = 4.20 q = 12 = = 15

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

5a + 3s = 460 a + s = 120 (–3) 5a + 3s = a – 3s = a = 50 2a = s = 120 s = 70

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

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

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

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

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 $ How many of each type of plant did he buy? f = flower plant n = non-flower 3.20f + 1.5n = f + n = 24

3.20f + 1.5n = f + n = 24 (–15) 32f + 15n = f – 15n = f = 8 17f = n = 24 n = 16 (10)