In an A.P., the middle term is the average of the other two terms. Thus, we have:
\[
7 = \frac{(2x - 1) + 3x}{2}.
\]
Multiply both sides by 2:
\[
14 = (2x - 1) + 3x \quad \Rightarrow \quad 14 = 5x - 1.
\]
Solving for \( x \):
\[
14 + 1 = 5x \quad \Rightarrow \quad 15 = 5x \quad \Rightarrow \quad x = \frac{15}{5} = 3.
\]
Thus, the value of \( x \) is \( \boxed{4} \).