Выполните вычитание:

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