You have the following information:
JK = 3x + 18
NO = 18
You can notice that segment JM and MK are equal, furthermore, JK = JM + MK.
Then, JK = 2JM. From this expression you obtain:
JM = JK/2
By replacing the given expression for JK you have:
JM = (3x + 18)/2 = 3/2 x + 9
Moreover, you can notice that segments JM and NO are qual. Then, you have:
JM = NO you replace the expressions for JUM and NO
3/2 x + 9 = 18 subtract 9 both sides
3/2 x = 18 - 9
3/2 x = 9 multiply both sides by 2/3
x = 9(2/3)
x = 18/3
x = 6
Hence, the value of x is x = 6
