To find the value of \( x \) using the relationship between vertical angles, we can examine the angles given in the problem.
We know that vertical angles are equal. In this case, angles \( \angle 1 \) and \( \angle 4 \) are vertical angles, so:
\[ m\angle 1 = m\angle 4 \]
Given that \( m\angle 1 = 125^\circ \) and \( m\angle 4 = (x + 35)^\circ \), we can set up the equation:
\[ 125 = x + 35 \]
Now, this equation will help us solve for \( x \). Thus, the equation that will solve for \( x \) is:
\[ x + 35 = 125 \]