How could i find jm ? what is my first move ?

Since you didn't answer i think JL is x+26
JK=x+26-x-22=4
KM=19
JM=4+19=23

Since there are no images given for the problem, i will define the parabola. a parabola is an open curve that is formed when a cone is sliced parallel to the side of it. the key aspects of a parabola when it is graphed looks like a curve that opens upward, downward, leftward or rightward. it has a latus rectum which is the length of the ends of a curved line. the directrix is the distance between the vertex of a parabola and the line. the vertex is the point where the curve ends.