D and E are the ones that aren’t functions because they use the x-values more then once
Step-by-step explanation:
(b) If
then
Note that
cancel out so we get

Solving for
we get

(c) I'm not sure what the problem is asking for but here goes. As r doubles,
becomes

Answer: 14
Step-by-step explanation:
- Degrees of freedom is the number of values in the evaluation of a test statistic that are free to vary.
For t-statistic , the degree of freedom for a sample with sample size 'n' is given by :-

Given : Sample size : n-1
Then, the number of degrees of freedom the t-value will have :-

Hence, the t-value will have 14 degrees of freedom.
My best guss would just try to get x by its self