<h3>
System of equations.</h3>

Put (1) to (2):

Substitute the value of x to (1):

Solution:

Answer:
The correct answer is OB.
Step-by-step explanation:
Let us recall the Associative Property of Addition: given three real numbers
,
and
the following equality holds:
.
Let us remark that the Associative Property of Addition tells us that we can perform the sums in any order. So,
.
In the other options there was used the Commutative Property of Addition.
Answer:
She should have multiplied one half (4)(3.5) by 5 squared.
Step-by-step explanation:
We are given that
Base of triangle=b=4 cm
Height of triangle=h=3.5 cm
Area of triangle=
After enlarged
Scale factor=5
New base of enlarged triangle=b'=4(5) cm
Height of enlarged triangle=h'=3.5(5) cm
Area of enlarged triangle=
But Beth wrote
Area of enlarged triangle=
She should have multiplied one half (4)(3.5) by 5 squared.
Answer:
And using the normal standard table or excel we find the probability:

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 avergae number of weeks an individual is unemployed of a population, and for this case we know the distribution for X is given by:
Where
and
Since the distribution for X is normal then, the distribution for the sample mean
is given by:
We select a sample of n =50 people. And we want to find the following probability
And using the normal standard table or excel we find the probability:
