standard_description: Understand that rational expressions form a system analogous to the rational numbers, closed under addition, subtraction, multiplication, and division by a nonzero rational expression; add, subtract, multiply, and divide rational expressions.
problem_activity: Task
Is the quadrilateral with vertices  $(-6, 2)$, $(-3,6)$, $(9, -3)$, $(6,-7)$
a rectangle? Explain.


aligns: no