Line RS line RT and line ST
Answer with Step-by-step explanation:
We are given that A, B and C are subsets of universal set U.
We have to prove that

Proof:
Let x
Then
and 
When
then
but 
Therefore,
but 
Hence, it is true.
Conversely , Let
but 
Then
and
When
then 
Therefor,
Hence, the statement is true.
42
Factors of 42:1,2,3,6,7,21,42
Factors of 84: 1,2,3,6,7,12,14,21,28,42,84
Both have 42 so it is the gcf.
Brainliest?
Answer:

Step-by-step explanation:
A confidence interval is "a range of values that’s likely to include a population value with a certain degree of confidence. It is often expressed a % whereby a population means lies between an upper and lower interval".
The margin of error is the range of values below and above the sample statistic in a confidence interval.
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".
In order to find the critical value we need to take in count that we are finding the critical value for the population mean and without the standard deviation, so on this case we need to use the t distribution. Since our interval is at 95% of confidence, our significance level would be given by
and
. We need to calculate the degrees of freedom are given by:

We can find the critical value using the following excel codes:
"=T.INV(0.025;38)" or "T.INV(1-0.025;38)"
And the critical values would be given by:
