We know:

and

These expressions have an
term in common. We can combine them if we can find forms of the expressions in terms of
:


Now, because
(by the reflexive property), we can write:

This is our answer, A.
Answer:
b
Step-by-step explanation:
In a 30-60-90 right triangle, the hypotenuse is twice the length of the short leg.
The hypotenuse is AB and is 18.
The short leg is BC and is 9.
The only choice with BC = 9 is b.
Answer: b
Answer:
The bulbs should be replaced each 1436.9 hours.
Step-by-step explanation:
Problems of normally distributed samples are solved using the z-score formula.
In a set with mean
and standard deviation
, the zscore of a measure X is given by:

The Z-score measures how many standard deviations the measure is from the mean. After finding the Z-score, we look at the z-score table and find the p-value associated with this z-score. This p-value is the probability that the value of the measure is smaller than X, that is, the percentile of X. Subtracting 1 by the pvalue, we get the probability that the value of the measure is greater than X.
In this problem, we have that:

How often should the bulbs be replaced so that no more than 1% burn out between replacement periods?
This is the first percentile of hours. So it is X when Z has a pvalue of 0.01.
So it is X when Z = -2.33.




The bulbs should be replaced each 1436.9 hours.
Answer:
i have made it in above picture
Х - 15 = 32
х = 32 + 15
x = 47 (answer)
-----------------------
47 - 15 = 32
32 = 32
х - 7.2 = 23,1
х = 23,1 + 7.2
х = 30,3 (answer)
---------------------------
30,3 - 7,2 = 23,1
23,1 = 23,1