[tex]x {}^{2} - 36 = x {}^{2} - 6 {}^{2} = (x + 6)(x - 6)[/tex]
a² - b² = (a+b)(a-b)
[tex]x {}^{2} - 12x + 6[/tex]
Cred că era + 36 nu + 6
[tex]x {}^{2} - 12x + 36 = \\ = x {}^{2} - 2 \times x \times 6+ 6 {}^{2} = \\ = (x - 6) {}^{2} [/tex]
(a-b)²= a² -2ab +b²
[tex] \frac{x {}^{2} - 36 }{ {x}^{2} - 12x + 36} = \\ \\ = \frac{(x + 6)(x - 6)}{(x - 6) {}^{2} } {}^{( \: (x - 6)} = \\ \\ \huge= \frac{x + 6}{x - 6} [/tex]
