We are to find the length of the segment of the line \( x + 1 = 0 \) (i.e., vertical line \( x = -1 \)) between two other lines.
Substitute \( x = -1 \) into both lines:
First line:
\[
3(-1) + 2y = 5 \Rightarrow -3 + 2y = 5 \Rightarrow 2y = 8 \Rightarrow y = 4
\]
Second line:
\[
3(-1) + 2y = 3 \Rightarrow -3 + 2y = 3 \Rightarrow 2y = 6 \Rightarrow y = 3
\]
So the points of intersection are:
- \( A = (-1, 4) \)
- \( B = (-1, 3) \)
These lie on a vertical line, so:
\[
\text{Length of intercept} = |4 - 3| = \boxed{1}
\]