Vertical angles are equal, so we have:
\[ m∠1 = m∠3 \]
Given that \( m∠1 = (2x + 26)° \) and \( m∠3 = 14° \), we can set up the equation:
\[ 2x + 26 = 14 \]
Now, let's solve for \( x \).
- Subtract 26 from both sides:
\[ 2x = 14 - 26 \]
\[ 2x = -12 \]
- Divide both sides by 2:
\[ x = -\frac{12}{2} \]
\[ x = -6 \]
Thus, the value of \( x \) is:
\[ \boxed{-6} \]