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