Solve for n:
-5(n + 6) = 3(7 + 3n) + 3n

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

We just started the introduction into circles and i have no idea how to do this.

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.