24. Представьте в виде дроби выражение: 1) $$\frac{4}{a} + \frac{7}{b}$$; 2) $$\frac{9}{m} - \frac{5}{mn}$$; 3) $$\frac{4}{12xy} - \frac{11}{18xy}$$; 4) $$\frac{5m}{3ab} + \frac{2m}{5a^2b} - \frac{7p}{2ab^2}$$; 5) $$\frac{3a-4b}{a} + \frac{8a^2 + 4b^2}{a^2 + 4b^2} - \frac{ab}{a^2 + 4b^2}$$; 6) $$\frac{3c^2 - 2c + 4}{bc^2} - \frac{2c - 9}{bc}$$; 25. Выполните действия: 1) $$\frac{x-3}{3x + 6} - \frac{x-6}{x+2}$$; 2) $$\frac{m+4}{5m-10} + \frac{3-m}{4m - 8}$$; 3) $$\frac{y+6}{y-6} - \frac{y+2}{y + 6}$$; 4) $$\frac{3x}{4x-4} + \frac{7}{7-7x}$$; 5) $$\frac{2b}{2b + c} - \frac{5x}{4b^2 + 4bc + c^2}$$; 6) $$\frac{2}{a^2-9} - \frac{1}{a^2 + 3a}$$

24. Представьте в виде дроби выражение:

1. $$\frac{4}{a} + \frac{7}{b} = \frac{4b + 7a}{ab}$$
2. $$\frac{9}{m} - \frac{5}{mn} = \frac{9n - 5}{mn}$$
3. $$\frac{4}{12xy} - \frac{11}{18xy} = \frac{1}{3xy} - \frac{11}{18xy} = \frac{6 - 11}{18xy} = -\frac{5}{18xy}$$
4. $$\frac{5m}{3ab} + \frac{2m}{5a^2b} - \frac{7p}{2ab^2} = \frac{50a m b + 12m b - 105ap}{30 a^2 b^2}$$
5. $$\frac{3a-4b}{a} + \frac{8a^2 + 4b^2}{a^2 + 4b^2} - \frac{ab}{a^2 + 4b^2} = \frac{(3a-4b)(a^2 + 4b^2) + a(8a^2 + 4b^2) - a(ab)}{a(a^2 + 4b^2)} = \frac{3a^3 + 12ab^2 - 4a^2b - 16b^3 + 8a^3 + 4ab^2 - a^2b}{a(a^2 + 4b^2)} = \frac{11a^3 - 5a^2b + 16ab^2 - 16b^3}{a(a^2 + 4b^2)}$$
6. $$\frac{3c^2 - 2c + 4}{bc^2} - \frac{2c - 9}{bc} = \frac{3c^2 - 2c + 4 - c(2c - 9)}{bc^2} = \frac{3c^2 - 2c + 4 - 2c^2 + 9c}{bc^2} = \frac{c^2 + 7c + 4}{bc^2}$$

25. Выполните действия:

1. $$\frac{x-3}{3x + 6} - \frac{x-6}{x+2} = \frac{x-3}{3(x+2)} - \frac{x-6}{x+2} = \frac{(x-3) - 3(x-6)}{3(x+2)} = \frac{x-3 - 3x + 18}{3(x+2)} = \frac{-2x + 15}{3(x+2)}$$
2. $$\frac{m+4}{5m-10} + \frac{3-m}{4m - 8} = \frac{m+4}{5(m-2)} + \frac{3-m}{4(m - 2)} = \frac{4(m+4) + 5(3-m)}{20(m-2)} = \frac{4m + 16 + 15 - 5m}{20(m-2)} = \frac{-m + 31}{20(m-2)}$$
3. $$\frac{y+6}{y-6} - \frac{y+2}{y + 6} = \frac{(y+6)^2 - (y+2)(y-6)}{(y-6)(y+6)} = \frac{y^2 + 12y + 36 - (y^2 - 6y + 2y - 12)}{y^2 - 36} = \frac{y^2 + 12y + 36 - y^2 + 4y + 12}{y^2 - 36} = \frac{16y + 48}{y^2 - 36} = \frac{16(y+3)}{(y-6)(y+6)}$$
4. $$\frac{3x}{4x-4} + \frac{7}{7-7x} = \frac{3x}{4(x-1)} + \frac{7}{-7(x-1)} = \frac{3x}{4(x-1)} - \frac{1}{x-1} = \frac{3x - 4}{4(x-1)}$$
5. $$\frac{2b}{2b + c} - \frac{5x}{4b^2 + 4bc + c^2} = \frac{2b}{2b + c} - \frac{5x}{(2b + c)^2} = \frac{2b(2b + c) - 5x}{(2b + c)^2} = \frac{4b^2 + 2bc - 5x}{(2b + c)^2}$$
6. $$\frac{2}{a^2-9} - \frac{1}{a^2 + 3a} = \frac{2}{(a-3)(a+3)} - \frac{1}{a(a+3)} = \frac{2a - (a-3)}{a(a-3)(a+3)} = \frac{2a - a + 3}{a(a-3)(a+3)} = \frac{a+3}{a(a-3)(a+3)} = \frac{1}{a(a-3)}$$