What is the hanger balance for 2x+y=15

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.

Can someone me with this? i’m not sure what to put for my equations.

Factor the following expression completely 6x^11-24x^7