2.)the resale value of a textbook decreases by 25% with each previous owner. a new textbook is sold for $85. which function represents the resale value of the textbook after x owners?
f(x) = 85(1 – 0.25)^x
f(x) = 85(1 + 0.25)^x
f(x) = 85(0.25)^x
f(x) = (85 – 0.25)^x

Set $r$ is a set of rectangles such that (1) only the grid points shown here are used as vertices, (2) all sides are vertical or horizontal and (3) no two rectangles in the set are congruent. if $r$ contains the maximum possible number of rectangles given these conditions, what fraction of the rectangles in set $r$ are squares? express your answer as a common fraction.