How do i get negative points (dont delete ansers)

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.

Simplify the rational expression. state any restrictions on the variable. t^2-4t-12 / t-8 the / is a fraction sign.

If a + b = 4, what is the value of |4 – a| + |4 – b|?