Single Fraction Simplify
1. We are asked to express the expression $$\frac{y^2}{y^2 - x^2} - \frac{y}{y - x}$$ as a single simplified fraction.
2. Start by recognizing that the denominator $$y^2 - x^2$$ is a difference of squares, which factors as:
$$
y^2 - x^2 = (y - x)(y + x)
$$
3. Rewrite the expression with this factorization:
$$
\frac{y^2}{(y - x)(y + x)} - \frac{y}{y - x}
$$
4. To combine the fractions, find a common denominator. The second fraction lacks the factor $$y + x$$ in the denominator, so multiply numerator and denominator by $$y + x$$:
$$
\frac{y^2}{(y - x)(y + x)} - \frac{y(y + x)}{(y - x)(y + x)}
$$
5. Now that both fractions have denominator $$ (y - x)(y + x) $$, combine the numerators:
$$
\frac{y^2 - y(y + x)}{(y - x)(y + x)}
$$
6. Simplify the numerator:
$$
y^2 - y(y + x) = y^2 - y^2 - yx = -yx
$$
7. So the expression becomes:
$$
\frac{-yx}{(y - x)(y + x)}
$$
8. Therefore, the simplified single fraction is:
$$
-\frac{yx}{(y - x)(y + x)}
$$