Answer:
x=7.4
Step-by-step explanation:
2.4+x=9.8
(x=9.8-2.4)
x=7.4
Answer:
21. y = 75000·0.935^t
22. after 74.6 days
23. y = 27.8112·1.18832^t
24. 18.8% per month
25. 1748
Step-by-step explanation:
22. It is convenient to use the graphing calculator to solve this problem. The number of days is where the exponential curve has the value 500. It is about 74.55 days. (see the first attachment)
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23. y = 27.8112·1.18832^t (see the second attachment)
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24. The rate of change is the difference between the base of the exponential and 1, often expressed as a percentage. The time period is the units of t.
(1.18832 -1) × 100% ≈ 18.8% . . . . per month
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25. Evaluating the function for t=24 gives y ≈ 1748.30425259 ≈ 1748.
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<em>Comment on graphing calculator</em>
A graphing calculator can make very short work of problems like these. It is worthwhile to get to know how to use one well.
Answer:
k=4
Step-by-step explanation:
First, we can subtract 3k on both sides. It is ultimately easier to start by subtracting the term with a variable. This would result in 45=5k+25. Then, we can subtract 25 on both sides to get closer to isolating k. This becomes 20=5k. We can then divide by 5 on both sides. This means that k=4.
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Explanation:</h2><h2>
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Here we know that Margie is standing on a bridge looking at the river. She throws a rock over the bridge with an initial velocity of 60 ft/sec. The height, h, of the rock at the rime t seconds after it was thrown can be modeled by the equation:

To calculate how long will it take for the rock to reach the surface of the water, we need to set
. So:

Given that time can't be negative, we just choose the positive value. Therefore, <em>it will take 4.70 seconds for the rock to reach the surface water.</em>