A sample of 100 clients of an exercise facility was selected. Let x = the number of days per week that a randomly selected client uses the exercise facility. Frequency
3
12
2 30
3 27
4 11
5 9
6 8
Find the number that is 1.5 standard deviations BELOW the mean (Round your answer to three decimal places.)

The head librarian at the library of congress has asked her assistant for an interval estimate of the mean number of books checked out each day. the assistant provides the following interval estimate: from 740 to 920 books per day. what is an efficient, unbiased point estimate of the number of books checked out each day at the library of congress?

Aschool puts on a play. the play costs $1,200 in expenses. the students charge $4.00 for tickets. there will be one performance of the play in an auditorium that seats 500 people. what is the domain of the function that shows the profit as a function of the number of tickets sold?  

[10 points, algebra 2-simplifying complex fractions]according to my answer key the restrictions are -1 and 4. but why not positive 1?