A manufacturer determines that the number of drills it can sell is given by the formula D(p)=−4p2+160p−3 At what price will the manufacturer sell the maximum number of drills? $
At what price will the manufacturer sell the maximum number of drills? $

Write the equation for the parabola that has x− intercepts (−2,0) and (4,0) and y− intercept (0,4).

Reflect the point (7,0) across the y-axis

Kayla wants to find the width, ab, of a river. she walks along the edge of the river 65 ft and marks point c. then she walks 25 ft further and marks point d. she turns 90° and walks until her location, point a, and point c are collinear. she marks point e at this location, as shown. (a) can kayla conclude that δ and δ are similar? why or why not? (b) suppose de = 15 ft. what can kayla conclude about the width of the river?