The expression is (15+6) */* 3. This is because we add up all the costs to get the total, and divide the total by three because there are three friends splitting the cost.
Answer:
x<=4, put the closed circle on "4" with the arrow going all the way left
Answer:
I think the answer I think the answer would be 14
Each curve completes one loop over the interval

. Find the intersections of the curves within this interval.

The region of interest has an area given by the double integral

equivalent to the single integral

which evaluates to

.
C because median is all about the middle