Study the given pattern carefully and select the number that can replace the question mark (?) in it.
The rectangle represents a set of calculations that are common across all the given equations. Identify the calculations involved and solve the fourth equation on the same basis:
7 â– 3 = \( \frac{11}{2} \)
6 â– 2 = \( \frac{13}{4} \)
5 â– 3 = 8
a â– b = ?
\(\frac{ab+1}{a}\)
\(\frac{ab}{a+b}\)
\(\frac{a+b}{ab-1}\)
\(\frac{ab+1}{a-b}\)