We know that if , then one of the following conditions need to be satisfied:

i. p = q

ii. n = p + q

From the problem we can say that,

⇒ x≠x + 2

So, the condition(ii) must be satisfied,

⇒ 18 = x + x + 2

⇒ 2x = 16

⇒

⇒ x = 8.

∴ The value of x is 8.