Answer:
Below.
Step-by-step explanation:
Part A: 
Part B: Degree = 2, Classification = Quadratic
Part C: The polynomial is closed because it is multiplied. You CANNOT close under division.
Answer: f^{-1}(x) = 3-x/3
Step-by-step explanation: Let y = f(x) and rearrange making x the subject, that is...
1. y = - 3x + 3 ( add 3x to both sides )
2. 3x + y = 3 ( subtract y from both sides )
3. 3x = 3 - y ( divide both sides by 3 )
4. x = 3-y/3
Change x back into terms of y
f^{-1}(x) = 3-x/3
1. So, since Manuel bought 9 pounds and ate 3/4 of 1 pound, he has 8.25 pounds left (9 - 0.75 = 8.25)
2. Let us call "x" the cost of 1 pound of apples
3. (8.25) * (x) = $15
4. x = $1.81818 rounded to the nearest dollar is $2 / pound
The sample space has 36 possible pairs from 1,1 1,2 1,3 up to 6,5 and 6,6
(a). Three pairs add to 4 1,3 2,2 and 3,1 so P(4) = 3/36 = 1/12
(b). 6 pairs add to 7 so P(7) = 6/36 = 1/6
(c) 15 pairs add to less than 7 so P(<7) = 15/36 = 5/12