Найдите сумму или разность: 20/(a^2+ 4a) – 5/a.

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

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

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