9514 1404 393
Answer:
19) x = number of people; y = cost
20) (people, cost) = (15, 120) and (25, 200)
21) the rate of change is $8 per person
22) y = 8x
23) $320
Step-by-step explanation:
19) The problem statement tells you x is the number of people and y is the cost.
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20) Writing the pairs (people, cost), we have ...
(15, 120) and (25, 200)
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21) The rate of change can be found from the slope formula:
m = (y2 -y1)/(x2 -x1)
m = (200 -120)/(25 -15) = 80/10 = 8
The rate of change is $8 per person.
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22) In point-slope form, the rule is ...
y -y1 = m(x -x1)
y -120 = 8(x -15)
y = 8x -120 +120
y = 8x
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23) For x=40, y = 8(40) = 320
A party for 40 people will cost $320.
