The first three steps in writing f(x) = 40x + 5x2 in vertex form are shown. write the function in standard form. f(x) = 5x2 + 40x factor a out of the first two terms. f(x) = 5(x2 + 8x) form a perfect square trinomial. = 16 f(x) = 5(x2 + 8x + 16) – 5(16) what is the function written in vertex form? f(x) = 5(x + 4) – 80 f(x) = 5(x + 8) – 80 f(x) = 5(x + 4)2 – 80 f(x) = 5(x + 8)2 – 80

Which statement explains how you could use coordinate geometry to prove the opposite sides of a quadrilateral are congruent? a. use the slope formula to prove the slopes of the opposite sides are the same. b. use the slope formula to prove the slopes of the opposite sides are opposite reciprocals. c. use the distance formula to prove the lengths of the opposite sides are the same. d. use the distance formula to prove the midpoints of the opposite sides are the same.