Yes it does matter which way you subtract
Answer: 40000
Step-by-step explanation:
The formula to find the sample size is given by :-
, where p is the prior estimate of the population proportion.
Here we can see that the sample size is inversely proportion withe square of margin of error.
i.e. 
By the equation inverse variation, we have

Given :


Then, we have

Hence, the sample size will now have to be 4000.
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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Answer:
-4 1/4
Step-by-step explanation:
-7 3/4 + 3 1/2 = -4 1/4