Сократите дробь (a^2-12a+36)/(36-a^2).

\[\frac{a^{2} - 12a + 36}{36 - a^{2}} = \frac{(6 - a)^{2}}{(6 - a)(6 + a)} =\]

\[= \frac{6 - a}{6 + a}\]