We can turn this word problem into the following equation:
x^2 + 85 = (x - 17)^2
x^2 + 85 = x^2 - 34x + 289
-85 -85
_______________________
x^2 = x^2 - 34x + 204
+34x +34x
_______________________
x^2 + 34x = x^2 + 204
-x^2 -x^2
____________________
34x = 204
Divide 34 on both sides
x = 6.
The number is 6.
Using the Empirical Rule, it is found that her finishing time will be between 70 and 82 seconds in 95% of her races.
<h3>What does the Empirical Rule state?</h3>
It states that, for a normally distributed random variable:
- Approximately 68% of the measures are within 1 standard deviation of the mean.
- Approximately 95% of the measures are within 2 standard deviations of the mean.
- Approximately 99.7% of the measures are within 3 standard deviations of the mean.
In this problem, the mean is of 76 seconds and the standard deviation is of 3 seconds, then:
76 - 2 x 3 = 70.
76 + 2 x 3 = 82.
Which means that values between 70 and 82 seconds are within 2 standard deviations of the mean, hence the percentage is of 95%.
More can be learned about the Empirical Rule at brainly.com/question/24537145
Answer:
Area=1/2bh
Given area of 36m^2
1/2(x)(x-1)=36
Multiply both sides by 2 to remove deminator
(x)(x-1)=72
X^2-x=72
X^2-x-72=0 then factor
(x-9)(x+8)=0
X=9,-8 however since area must be positive, take the absolute value of 8
1/2(9m*8m)=36m^2
