1. We don't know what are D and E, but some answers are always true.
DE is the perpendicular bisector of JL so DE and JL are perpendicular and B) is always true.
Moreover, from definition it passes through the midpoint of JL, so K is a midpoint and C) is true.
Triangles JKD and LKD are right triangles and both have equal legs (first one KD and the second KL=KJ), so they are congruent and DJ = DL (answer D) is true).
So the one that is not necessarily true is A).
2.
This is a right triangle, so its circumcenter is a midpoint of a hypotenuse.
[tex]M=\left(\dfrac{-1+(-4)}{2},\dfrac{-4+0}{2}\right)=\left(\dfrac{-1-4}{2},\dfrac{-4}{2}\right)=\boxed{\left(-\dfrac{5}{2},-2\right)}[/tex]
Answer B)
