Since \( m\angle 1 \) and \( m\angle 3 \) are vertical angles, they are equal. Therefore, we can set up the equation:
\[ m\angle 1 = m\angle 3 \]
Substituting the given expressions:
\[ (2x + 26) = 14 \]
Now, we can solve for \( x \):
- Subtract 26 from both sides:
\[ 2x = 14 - 26 \]
\[ 2x = -12 \]
- Divide both sides by 2:
\[ x = -6 \]
Thus, the value of \( x \) is \( \boxed{-6} \).