Answer :

If K is midpoint of JL then JK = 0.5JL

JL = 4x - 2; JK = 7

The equation:
0.5(4x - 2) = 7
2x - 1 = 7      |add 1 to both sides
2x = 8        |divide both sides by 2
x = 4

JL = 4(4) - 2 = 16 - 2 = 14

KL = JK = 7