Выполните вычитание 20/(a^2+5a)-4/a.

\[\frac{20}{a^{2} + 5a} - \frac{4}{a} = \frac{20}{a(a + 5)} - \frac{4^{\backslash a + 5}}{a} =\]

\[= \frac{20 - 4a - 20}{a(a + 5)} = - \frac{4a}{a(a + 5)} = - \frac{4}{a + 5}\]