Answer:
Step-by-step explanation:

Answer:
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Step-by-step explanation:
1) The ratio of used books to all books is 6:14
2) The ratio of used books to new books is 6:8
Using a linear function, it is found that the product rs is rs = 81.
<h3>What is a linear function?</h3>
A linear function is modeled by:
y = mx + b
In which:
- m is the slope, which is the rate of change, that is, by how much y changes when x changes by 1.
- b is the y-intercept, which is the value of y when x = 0, and can also be interpreted as the initial value of the function.
In this problem, when x changes by 68(from -64 to 68), y changes by -16(from 12 to -4), hence the slope is given by:
m = -16/64 = -0.25.
Hence:
y = -0.25x + b.
When x = 34, y = -4, hence this is used to find b.
-4 = -0.25(34) + b
b = 4.5.
Hence the function is:
y = -0.25x + 4.5.
f(r) = 0, hence:
-0.25x + 4.5 = 0
x = 4.5/0.25
x = 18
r = 18.
f (0) = s, hence s = 4.5.
Then the value of the product is:
rs = 18 x 4.5 = 81.
More can be learned about linear functions at brainly.com/question/24808124
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10 dollars i got this by finding 4 times 2 is 8 and half of 4 is 2 so it is exactly 10 dollars