Упростите выражение: 5a/(a+3)+(a-6)/(3a+9)•135/(6a-a^2).

\[\frac{5a}{a + 3} + \frac{a - 6}{3a + 9} \cdot \frac{135}{6a - a^{2}} =\]

\[= \frac{5a^{\backslash a}}{a + 3} - \frac{45}{a(a + 3)} =\]

\[= \frac{5a^{2} - 45}{a(a + 3)} = \frac{5 \cdot \left( a^{2} - 9 \right)}{a(a + 3)} =\]

\[= \frac{5 \cdot (a - 3)}{a}\]