a-b/a2-b2

The expression \( \frac{a - b}{a^2 - b^2} \) can be simplified using the difference of squares.

Recall that:

\[ a^2 - b^2 = (a - b)(a + b) \]

Now, we can rewrite the original expression:

\[ \frac{a - b}{a^2 - b^2} = \frac{a - b}{(a - b)(a + b)} \]

If \( a \neq b \), we can cancel \( a - b \) from the numerator and denominator:

\[ = \frac{1}{a + b} \]

So, the simplified form of \( \frac{a - b}{a^2 - b^2} \) is:

\[ \frac{1}{a + b} \quad \text{(for \( a \neq b \))} \]