4. At Sports Shoe Warehouse, the cost of 9 pairs of baseball shoes is $855 plus $92 for each additional pair. From Winning Team Shoes, the cost of 9 pairs of baseball shoes is $810 plus an additional 7% for each
additional pair. For how many total pairs of baseball shoes does each vendor cost about the same?

What is always true about a positive integer raised to a negative odd power?

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.

Which is the focus of a parabola with equation y2=4x