Answer:




Step-by-step explanation:
Given

Required
Solve (a) to (d)
Using tan formula, we have:

This gives:

Rewrite as:

Using a unit ratio;

Using Pythagoras theorem, we have:




Take square roots of both sides

So, we have:


Solving (a):

This is calculated as:


Where:


So:




Solving (b):

This is calculated as:

Where:
---- given
So:


Solving (c):

In trigonometry:

Hence:

Solving (d):

This is calculated as:


Where:


So:



Answer:



Step-by-step explanation:
Given

Solving (a): Point estimate of difference of mean
This is calculated as: 


Solving (b): 90% confidence interval
We have:


Confidence level is: 



Calculate 


The z score is:

The endpoints of the confidence level is:






Split


Hence, the 90% confidence interval is:

Solving (c): 95% confidence interval
We have:


Confidence level is: 



Calculate 


The z score is:

The endpoints of the confidence level is:






Split


Hence, the 95% confidence interval is:

Hi there, it's really not 4 terms it actually 3 terms, I will explain why. If you combine the 2x with the x that would give you 3 terms, not 4 terms. So, there are 3 terms in it, you have to make sure to simplify it.
100 dollars should be a one time fee so that has to be added to the equation, and since it is a one time fee it should not have a variable next to it.
It also says that you have to pay 720 dollars per month, so it has to have a variable next to it to show the number of months that she needs to pay that amount of money.
The answer should be D.
y= 720x +100