Помогите решить пример по алгебре

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$\frac{2}{x - 4} - \frac{x + 8}{(x - 4)(x + 4)} - \frac{1}{x} \\ \frac{2x \times (x + 4) - x \times (x + 8) - (x - 4) \times (x + 4)}{x \times (x {}^{2} - 16) } \\ \frac{2x {}^{2} + 8x - x {}^{2} - 8x - (x {}^{2} - 16)}{x \times (x {}^{2} - 16)} \\ \frac{2x {}^{2} - x {}^{2} - x {}^{2} + 16}{x {}^{3} - 16x} \\ \frac{16}{x {}^{3} - 16x }$
ответ:
16/x^3- 16x