Упростите выражение $$\frac{5}{x-7} - \frac{2}{x} + \frac{3x+21}{x^2-49}$$

$$\frac{5}{x-7} - \frac{2}{x} + \frac{3x+21}{x^2-49} = \frac{5}{x-7} - \frac{2}{x} + \frac{3(x+7)}{(x-7)(x+7)} = \frac{5}{x-7} - \frac{2}{x} + \frac{3}{x-7} = \frac{5x}{x(x-7)} - \frac{2(x-7)}{x(x-7)} + \frac{3x}{x(x-7)} = \frac{5x-2x+14+3x}{x(x-7)} = \frac{6x+14}{x(x-7)} = \frac{2(3x+7)}{x(x-7)}$$