Answer:
c. (x +3)(x + 1)
Step-by-step explanation:
Factoring an equation is a way of expressing an equation as the product of other linear expressions. The following expression,

Can be represented as the product of the following,

To check this, one can distribute, one of the expressions over the other, then simplify, the result should be the starting expression,

Distribute,

Simplify,


Part a)
The simple random sample of size n=36 is obtained from a population with

and

The sampling distribution of the sample means has a mean that is equal to mean of the population the sample has been drawn from.
Therefore the sampling distribution has a mean of

The standard error of the means becomes the standard deviation of the sampling distribution.

Part b) We want to find

We need to convert to z-score.

Part c)
We want to find

We convert to z-score and use the normal distribution table to find the corresponding area.

Part d)
We want to find :

We convert to z-scores and again use the standard normal distribution table.

We can use the substitution method to solve this problem.
The second equation is

, so we can plug in 2x for 'y' in the first equation:


Multiply:

Combine like terms:

This is the x-value of our solution, we can plug this into any of the two equations to find the y-value:


Multiply:

This is the y-value of our solution. So our entire solution is (3, 6).