What is the value of x?

It can be seen in the given figure that ∠DCB and ∠DCX form a linear pair.

∴ ∠DCB + ∠DCX = 180°

⇒ ∠DCB + 139° = 180°

⇒ ∠DCB = 180° − 139° = 41°

It is known that opposite angles of a cyclic quadrilateral are supplementary.

∴ ∠DAB + ∠DCB = 180°

⇒ 3x − 2° + 41°= 180°

⇒ 3x + 39° = 180°

⇒ 3x = 180° − 39° = 141°

$\Rightarrow x=\frac{1}{3}\times 141°=47°$

Thus, the value of x is 47°.