fskilnik@GMATH wrote:GMATH practice exercise (Quant Class 3)
$$? = \frac{{{x^2} - {y^2}}}{{xy}} - \frac{{xy - {y^2}}}{{xy - {x^2}}}\,\,\,$$
$$\frac{{xy - {y^2}}}{{xy - {x^2}}} = \frac{{y\left( {x - y} \right)}}{{x\left( {y - x} \right)}} = \underleftrightarrow {\frac{{ - y\left( {y - x} \right)}}{{x\left( {y - x} \right)}}} = \frac{{ - y}}{x}$$
$$? = \frac{{{x^2} - {y^2}}}{{xy}} + \frac{y}{x} = \underleftrightarrow {\frac{{{x^2} - {y^2}}}{{xy}} + \frac{{y \cdot y}}{{x \cdot y}} = \frac{{{x^2}}}{{xy}}} = \frac{x}{y}\,\,\,\,\,\,\, \Rightarrow \,\,\,\,\,\,\,\left( A \right)$$
We follow the notations and rationale taught in the GMATH method.
Regards,
Fabio.