1. Every person at a party of twenty-eight people said hello to each of the other people at the party exactly once. How many "hello's" were said at the party?

Use the graph to determine the range. which notations accurately represent the range? check all that apply. (–∞, 2) u (2, ∞) (–∞, –2) u (–2, ∞) {y|y ∈ r, y ≠ –2} {y|y ∈ r, y ≠ 2} y < 2 or y > 2 y < –2 or y > –2

Sh what is the value of x? ox= 2.25 x = 11.25 ox= x = 22 1 (2x + 10) seo - (6x + 1) -- nie

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.