Answer:
27 units
Explanation:
A midpoint divides a line segment into two congruent parts. K being the midpoint of segment JL means ...
JK = KL
8x +11 = 14x -1 . . . . . substitute given expressions
12 = 6x . . . . . . . . add 1 -8x
2 = x . . . . . . . . divide by 6
Then the length of JK is ...
8x +11 = 8(2) +11 = 27
JK is 27 units long.
_____
Additional comment
KL = JK = 27 units
JL = 2(27 units) = 54 units