Выполнить действия 1) ((х-8)/4х^2)-((5-12х)/6х^3) 2) (20/(a^2+4a))-(5/a)...

1) $\frac{x- 8}{4 x^{2} } - \frac{5 - 12x}{6x ^{3} } = \frac{3 x^{2} - 24x - 10+ 24x}{12 x^{3} } = \frac{3 x^{2}- 10 }{12 x^{3} }$
2) $\frac{20}{a ^{2} + 4a } - \frac{5}{a} = \frac{20}{a(a+4)} - \frac{5}{a} = \frac{20 - 5a - 20}{a(a+4)} = \frac{-5a}{a(a+4)} = - \frac{5}{a+4}$
3) $\frac{14 p^{2} }{7p+3} - 2p = \frac{14 p^{2}- 14 p^{2}- 6p }{7p+3} = - \frac{ 6p}{7p+3}$
4) $\frac{ m^{2} }{ m^{2} - 9 } - \frac{m}{m+3} = \frac{m ^{2} }{(m+3)(m-3)} - \frac{m}{m+3} = \frac{ m^{2}- m^{2}+ 3m }{(m+3)(m-3)} = \frac{3m}{ m^{2} - 9}$