What value of p makes the equation below true?

The depth of a lake at a certain point, wich is a function of the distance of that point from shore, is 30 feet.

Problem fathi wants to print out a pdf document that is 48 pages long. to save paper, he decides to print on both sides of each sheet and to print two pages on each side of the sheet. how many sheets of paper will he need?

What is the equation of this graphed line? enter your answer in slope-intercept form in the box.