Answer:
B. 
Step-by-step explanation:
![\displaystyle x^2 = -8x - 7 → x^2 + 8x + 7 \\ \\ x^2 + 8x + 7 \\ [x + 1][x + 7]; -1, -7 = x](https://tex.z-dn.net/?f=%5Cdisplaystyle%20x%5E2%20%3D%20-8x%20-%207%20%E2%86%92%20x%5E2%20%2B%208x%20%2B%207%20%5C%5C%20%5C%5C%20x%5E2%20%2B%208x%20%2B%207%20%5C%5C%20%5Bx%20%2B%201%5D%5Bx%20%2B%207%5D%3B%20-1%2C%20-7%20%3D%20x)
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This is in 2 point form
(y2-y1)=m(x2-x1)
(9-5)=3/5(x-3)
x=29/3
She walks 6/5 of a mile in 1 hour
So, she walks 1.2 miles per hour
Using the t-distribution to build the 99% confidence interval, it is found that:
- The margin of error is of 3.64.
- The 99% confidence interval for the population mean is (19.36, 26.64).
<h3>What is a t-distribution confidence interval?</h3>
The confidence interval is:

In which:
is the sample mean.
- s is the standard deviation for the sample.
The critical value, using a t-distribution calculator, for a two-tailed 95% confidence interval, with 21 - 1 = 20 df, is t = 2.086.
The other parameters are given as follows:

The margin of error is given by:

Hence the bounds of the interval are:


The 99% confidence interval for the population mean is (19.36, 26.64).
More can be learned about the t-distribution at brainly.com/question/16162795
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Answer:
after 1 hr = 20 after 2 hrs =<em> </em> 40 after 3 hrs = 80 160 n 3 hrs