Answer:
x = 3
Explanation:
See the diagram attached.
We have a triangle Δ JMK and the line MB is a perpendicular drawn on JK from the vertex M.
Now, given that BJ = BK
Therefore, MB is the perpendicular bisector of side JK.
Hence, Δ JMK is a isosceles triangle with sides JM = MK
Hence, 9x - 18 = 3x {Since given that JM = 9x - 18 and MK = 3x}
⇒ 6x = 18
⇒ x = 3 (Answer)