What is an equation that is true for every value

Segment xz is bisected by point y. if xy = 12x, and the measure of xz = 18x – 6, solve for x

In two or more complete sentences, determine the appropriate model for the given data and explain how you made your decision. (1,-1), (2,0.5), (5,1.5), (8,2)

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?