Answer:
y = 5, -4
Step-by-step explanation:
To solve proportions you cross-multiply.
Now that we have 8 = y^2 - y - 12, we must make the entire trinomial equal to 0 by subtracting 8 from both sides.
y^2 - y - 20 = 0
Factor the trinomial.
(y - 5)(y + 4) = 0
Make both factors equal to 0 to solve for both values of y.
y = 5, -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:
Step-by-step explanation:
Given
Required
Find the slope
Subtract 2 from both sides
Open bracket
Take LCM
An equation has the form:
Where
By comparing: and
<em>So, the slope is 1/4</em>
