Part a there is a function f, where f(n) 1200n+ 3500 represents the number of people in a town who owned a smartphone n years after 2007. how many people owned a smartphone in this town in the year 2010? enter your answer in the box.

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.