Question 4(Multiple Choice Worth 1 points) (07.04 LC) Factor completely 49x2 − 9. (7x + 3)(7x − 3) (7x + 3)(x − 3) (7x − 3)(7x −
2 answers:
Answer:
A
Step-by-step explanation:
We take a look at this expression: and notice that both terms are square numbers.
and
.
There is a specific formula that I highly recommend you memorize involving differences of squares. It states that given the difference of squares , it can always be factored into
.
Here, we can apply that. In this case, a = 7x and b = 3. So:
Thus, the answer is A.
Hope this helps!
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Answer:
And we can find this probability with this difference:
And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.
Step-by-step explanation:
Previous concepts
Normal distribution, is a "probability distribution that is symmetric about the mean, showing that data near the mean are more frequent in occurrence than data far from the mean".
The Z-score is "a numerical measurement used in statistics of a value's relationship to the mean (average) of a group of values, measured in terms of standard deviations from the mean".
Solution to the problem'
Let X the random variable that represent the hous spent studying the week before final exams of a population, and for this case we know the distribution for X is given by:
Where and
We are interested on this probability
And the best way to solve this problem is using the normal standard distribution and the z score given by:
If we apply this formula to our probability we got this:
And we can find this probability with this difference:
And in order to find these probabilities we can use tables for the normal standard distribution, excel or a calculator.