The angles 2x and 36 are vertical angles, which means that they are angles opposite to the same vertex and thus they are equal:
Now we have to solve this equation to find the value of x.
To solve for x, divide both sides of the equation by 2:
On the left-hand side, the 2 on the numerator and the 2 on the denominator cancel each other and we are left only with x:
And on the right-hand side 36/2 is equal to 18:
Answer: x=18