(a+b)²-4ab=please help me for my exam
1 answer:
Answer:
Step-by-step explanation:
<h3>to understand this</h3><h3>you need to know about:</h3>- algebra
- algebraic identity:(a-b)²=(a+b)²-4ab
therefore
using the identity our answer is (a-b)²
let's prove it
- (a-b)²:a²-2ab+b²
- rewrite -2ab as 2ab-4ab:a²+b²+2ab-4ab
- use (a+b)²=a²+2ab+c²:(a+b)²-4ab
therefore
we have also proven that
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Answer:
So then we can conclude that we expect the middle 95% of the values within 18 and 30 minutes for this case
Step-by-step explanation:
For this case we can define the random variable X as the amount of time it takes her to arrive to work and we know that the distribution for X is given by:
And we want to use the empirical rule to estimate the middle 95% of her commute times. And the empirical rule states that we have 68% of the values within one deviation from the mean, 95% of the values within two deviations from the mean and 99.7 % of the values within 3 deviations from the mean. And we can find the limits on this way:
So then we can conclude that we expect the middle 95% of the values within 18 and 30 minutes for this case