Answer:
Explanation:
Binomial expansion is:

Here in given expression we have a=x , b=-2y and n = 13
general formula for binomial expansion is:

Since, 
r should be one number less than the term we need to find so it will become the number we need to find like here we have to find 9th term so, r=8
substituting the values in the genral formula we will get

After substituting the values we will get

After simplification we will get
which will be the 9th term of the expansion
Answer:
A) The mean of the chi-square distribution is 0
A) is not a property of chi square distribution.
Step-by-step explanation:
We have to find the properties of a chi square test.
A) False
The mean of a chi square distribution is equal to the degree of freedom.
B) True
The chi-square distribution is non symmetric.
C) True
The chi square value can be zero and positive.
It can never be negative because it is based on a sum of squared differences .
D) True
The chi-square distribution is different for each number of degrees of freedom.
When we are working with a single population variance, the degree of freedom is n - 1.
Answer: option d.
Step-by-step explanation:
You have the following formul given in the problem:

You know that:
The number of customers serviced in an hour by the technical support representative is 6 costumbers, therefore:

As the problem asked for the probability that a costumber will be on hold less than 30 minutes, we know that:

Substitute the values above into the formula.
Then, you obtain:
or 95%
Answer:
6 dm
Step-by-step explanation:
Triangle DBE is similar to triangle ABC, so their side lengths are proportional.
DE/AC = DB/AB
The length of DB can be found from ...
DB +AD = AB
DB = AB -AD = (15 -10) dm = 5 dm
So, we can fill in the proportion:
DE/(18 dm) = (5 dm)/(15 dm)
DE = (18 dm)·(1/3) . . . . . . . . . . simplify, multiply by 18 dm
DE = 6 dm
_____
It can be helpful to draw and label a figure.
Answer:

Step-by-step explanation:

When we factor expressions, we look for factors within the terms that are alike, or in other words, we look for common factors. Here,
and
only have one common factor:
. Therefore, to factorize this expression, divide both terms by
.

Now, we've "carried"
out of the expression and have therefore factored it.
I hope this helps!