What is: six more than the product of 21

If square root x = -7, then x= -49 true or false

Ateacher noticed 5/8 of the students were wearing either blue shorts or white shorts. write two different ways this could be done.

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.