Answer :

Certainly! Let's simplify the given expression step-by-step:

We start with the expression:
[tex]\[ \frac{x^{-1} - y^{-1}}{x - 1 + y - 1} \][/tex]

### Step-by-Step Simplification:

1. Simplify the Exponents and the Denominator:
- We can rewrite [tex]\(x^{-1}\)[/tex] as [tex]\(\frac{1}{x}\)[/tex] and [tex]\(y^{-1}\)[/tex] as [tex]\(\frac{1}{y}\)[/tex]:
[tex]\[ \frac{\frac{1}{x} - \frac{1}{y}}{x - 1 + y - 1} \][/tex]
- Combine like terms in the denominator:
[tex]\[ x - 1 + y - 1 = x + y - 2 \][/tex]
- So the expression now looks like this:
[tex]\[ \frac{\frac{1}{x} - \frac{1}{y}}{x + y - 2} \][/tex]

2. Combine the Numerator into a Single Fraction:
- We need a common denominator for the fractions in the numerator:
[tex]\[ \frac{1}{x} - \frac{1}{y} = \frac{y - x}{xy} \][/tex]
So the expression becomes:
[tex]\[ \frac{\frac{y - x}{xy}}{x + y - 2} \][/tex]

3. Simplify the Compound Fraction:
- Dividing by a fraction is the same as multiplying by its reciprocal. Hence:
[tex]\[ \frac{y - x}{xy} \div (x + y - 2) = \frac{y - x}{xy} \cdot \frac{1}{x + y - 2} = \frac{y - x}{xy(x + y - 2)} \][/tex]

4. Simplify the Final Result:
- Notice that the numerator [tex]\(y - x\)[/tex] is the negation of [tex]\(x - y\)[/tex]. Therefore, we can write:
[tex]\[ \frac{y - x}{xy(x + y - 2)} \Rightarrow \frac{-(x - y)}{xy(x + y - 2)} = \frac{-1 \cdot (x - y)}{xy(x + y - 2)} \][/tex]

So the simplified form of the given expression is:
[tex]\[ \frac{-1}{y} + \frac{1}{x}\text{ all over }x + y - 2 \][/tex]

Putting it all together, we get:
[tex]\[ \boxed{\frac{-1/y + 1/x}{x + y - 2}} \][/tex]

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