A store owner estimates that by charging x dollars each for a certain brand of sunglasses, he can sell 40 2 pairs of sunglasses each week. The quadratic function R(x) = –22 + 40x is used to find the revenue, R, received when the
selling price of a pair of sunglasses is x. Find the selling price that will give him the maximum revenue, and then find the
amount of the maximum revenue.

Graph a triangle (xyz) and reflect it over the line y=x to create triangle x’y’z’. describe the transformation using words. draw a line segment from point x to the reflecting line, and then draw a line segment from point x’ to the reflecting line. what do you notice about the two line segments you drew? do you think you would see the same characteristics if you drew the line segment connecting y with the reflecting line and then y’ with the reflecting line? how do you know?