Unit D Homework Helper Answer Key

Transcription

1 Lesson -1 Recognizing a Function 1. D a.. a. No 4. No. a Yes 6. No. No 8. a. {(49, 1), (61, 6), (10, 2), (6, 2), (2, 2)} 9. Yes; answers will vary. 10. a. he relation is not a function. 14. a. Yes 1. a. A 16. a Yes 1. a. Yes c. A 11. a. Relation 2, Relation 12. Yes digits 20 Grade 8

2 6 (, 60) 480 (4, 480) c. 120x d. c. Only Relation P is a function. Lesson -2 Representing a Function 1. a.2 (1, 2) (2, ) 4 (, 4) y x 1 c. 2. a.0 (0, 0) 14 (16, 14) 21 (24, 21) y 8 x c a a. A a. he robot descends about 20 ft in about hr. 1,0 (, 10) 1,260 (4, 1260) 20 (10, 20) c. y 90x 1,620 d.. a (2, 240) 60 e. 18 hr 8. a.equat ion x 6 digits 21 Grade 8

3 c.6 (0, 6) (, ) 8 (6, 8) d. 2.. B 4. B. a. Every minute, the student has fewer problems to complete. 6. a. B. a a. 9. a. B a.9 (2, 9) 10 (4, 10) 11 (6, 11) y 1 2 x 8 c. x 4 9. a. A, C, E 0. c a. Each input must have only one output. You can draw a straight line through the graph of all the ordered pairs. Lesson - Linear Functions 1. a. c. No 11. a.2.2 his is the amount of water the faucet adds to the watering can each second. c. 19 sec Yes digits 22 Grade 8

4 Lesson -4 Nonlinear Functions 1. linear 2. a. Function II, Function III Function I. a. able I, able II B 4. a. nonlinear Check graphs.. a. Only able II 6. a. D nonlinear. a. nonlinear B c a. nonlinear Lesson - Increasing and Decreasing Intervals 1. Interval (a): an increasing Interval (b): a constant Interval (c): a decreasing Interval (d): a constant 2. a. (4), (2) () c. (1). a. 2 All of the increasing intervals indicate lengths of time when the speed is increasing. All of the increasing intervals start at 0 mph. c. he increasing intervals end at different speeds. 4. a. Interval (a): a constant Interval (b): a decreasing Interval (c): a constant Interval (d): an increasing. a. Identify the lines that have a slope of zero Interval (a): an increasing Interval (b): a constant Interval (c): an increasing Interval (d): a constant Interval (e): a decreasing. a. an increasing a decreasing c. a constant d. an increasing e. a constant 8. a. 1, 4, 2, c., 6 9. a. A 2 Lesson -6 Sketching a Function Graph D. a. 4. a. g S D t digits 2 Grade 8

5 . a. People are waiting for a train. A train comes and some people get on the train. he other people wait for the next train. Another train arrives and the other people get on. 6. B. H 8. a. he number of cars in the parking lot increases in the morning. hen the number of cars decreases in the afternoon. Later at night, more cars arrive steadily. Ashley did not include the interval where the number of cars in the parking lot decreases. 9. a. y 10. a. he beginning of the graph should show a line that is decreasing for the first 9 months. x 11. a. S 12. a. he horizontal line represents that after a certain time the total number of people remains constant here is a carnival in a park. During the first few hours people continue to arrive. For the next few hours the number of people remains the same. 1. a. he amount of money a company has goes up and then they have to pay their costs. his happens at the end of each month. Lesson - Problem Solving 1. a. 1 9 M c. B 2. a digits 24 Grade 8

6 . a.d c. A. a c. C 4. a.. a. 6. a. d. A D 90 4 sec a. hr 9. a.c c. d. D Lesson 8-1 Defining a Linear Function Rule 1. B 2. B. A 4. a. B. a. A linear function rule is an equation of the form y mx b, whose graph is a straight line. y 6x digits 2 Grade 8

7 6. a. B, C. a. B, C, D She graphed the equation y x. 8. C 9. B 10. a. B, C, E c. C 11. A 12. a. A, B C d. Answers will vary. 1. a. B Lesson 8-2 Rate of Change a. y 2x 2. a. Find the distance between the two points along the y-axis a. y 4x 4. a. 4 mm/wk he machinist did not divide by the change in time a. B c. 1, 4, 9, 14, a. 0 meters painted and 20.6 centimeters of paint a. 1.8 cm/min 8 min Lesson 8- Initial Value y x 2. a a m 6. a. D. a. Rate of change: 6, Initial value: 6 8. a. 6, C feet per second 10. a. A B 11. height: 0. mi change: 0.4 mph 12. D 1. a. A 0 c. A Lesson 8-4 Comparing wo Linear Functions 1. A 2. C. a. C C c. Somerville 4. B. a. A A c. A 6. a. E A c. C. a. functions A and D function B c. 4 digits 26 Grade 8

8 Lesson 8- Constructing a Function to Model a Linear Relationship 1. w 1 2 t 2. d 10t. y x y x 1. y 0.1x 8 6. y 0.1x.9. a. y 0.1x a. y x 8 18 inches 9. a. y x a. y 1.99x 1.99 $0 11. a. C y 2 9 x 12. a. C B 1. a. y 6.x C 1. a. B y x y x.1 1. y 1.x a. D Michael was 4 yr and months old when his little sister was born. 19. a. y 4 x 6 B Lesson 8-6 Problem Solving 1. a. c 6t 0 6 c. B 2. a. a t No. a. D D c. $1, a. B B. a. S 12w $1 c. C 6. a. y 6x 4,19. a. y 60 N heir supply will last 8 nights, with 4 logs left over. 8. a. B.6 c. Yes 9. a. C 4n 20 $8 c. 4 d. C digits 2 Grade 8