8b with explanation please

The square pyramid has a volume of 441 cubic inches. what is the value of x? 1/7x is the height x is the base

How do i simply this expression (quadratic formula basis) on a ti-84 or normal calculator?

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.