Answer:
a) 
b) 
Step-by-step explanation:
Total number of students = 52
Number of students who are democrats = 26
Number of students who are business majors = 12
Number of students who are business majors as well as democrats = 7
Now, lets come to the question.
a) Number of students who are democrats but not business majors = 
(Number of democrats) - (Number of democrats as well as business majors)
⇒ 26 - 7 
⇒ 19 
∴ P (Democrat who is not a business major) = 
b) Number of students who are neither democrats nor business majors = 
(Total number of students) - (Number of democrats + Number of business majors + Number of democrats as well as business majors)
⇒ 52 - (26 + 12 + 7)
⇒ 52 - 45
⇒ 7
∴ P (Neither democrat nor business major) = 