I NEED THE ANSWER(ASAP) The list below shows the allowance earned by eight of the students in Ms. Tomas's class. What is the mean allowance earned in Ms. Tomas's class?

$7, $12, $8.50, $ 10, $7, $8, $10.50, $11​

Which addition property is being illustrated below? (type commutative or associative) (6 + 7) + 1 = 6 + (7 + 1)

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.

Factor and solve to find roots x squared -x - 90 =0