1. The problem statement, all variables and given/known data Let U= all real numbers, A=[2,9), B=(0,1], C=[-1,4]. Express in interval notation: (A union B) - C 2. Relevant equations A union B includes all elements that are in either A or B, including any objects that happen to lie in both A and B. The difference A - B consists of all objects that are elements of A and are not elemnts of B 3. The attempt at a solution I think the interval is from (4,9). A union B would be (0,1]union[2,9], then you remove from [-1, 4]. The only reason why I don't know if I'm right is because of the gap in the union of A and B. I don't know if that has any effect on the answer. If (4,9) is correct then would it be safe to assume that (A union B) - C = A-C ?