11 points! :) Five times the quantity of a number increased by 3 is the same as 6 times the number minus 3. What is the number?

Will give brainliest sum of arithmetic series (sigma notation) find the numerical answer to the summation given below. (image shown below)

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.

Mila's dog weighs 4 pounds more than 8 times the weight of keiko's dog. which expression could be used to fine te weight of mila's dog?