Answer:
(a) moment generating function for X is 
(b) 
Step-by step explanation:
Given X represents the number on die.
The possible outcomes of X are 1, 2, 3, 4, 5, 6.
For a fair die, 
(a) Moment generating function can be written as
.



(b) Now, find
using moment generating function




Hence, (a) moment generating function for X is
.
(b) 
Answer:
-4x^2-28x
Step-by-step explanation:
Distribute
-4x(x) and -4x(-7)
-4x^2 and -28x