Write the solution set for the equation using set notation:

x^2 = -4

F(x)=x/2-2 and g(x)=2x^2+x-3 find (f+g)(x)

Quick! a survey of 57 customers was taken at a bookstore regarding the types of books purchased. the survey found that 33 customers purchased mysteries, 25 purchased science fiction, 18 purchased romance novels, 12 purchased mysteries and science fiction, 9 purchased mysteries and romance novels, 6 purchased science fiction and romance novels, and 2 purchased all three types of books. a) how many of the customers surveyed purchased only mysteries? b) how many purchased mysteries and science fiction, but not romance novels? c) how many purchased mysteries or science fiction? d) how many purchased mysteries or science fiction, but not romance novels? e) how many purchased exactly two types of books?

How many sides does a regular polygon have if each exterior angle measure is 45 degrees explain your answer, i really don't understand this.