Đáp án+Giải thích các bước giải:
`c) \frac{x²}{x² - x} - \frac{x²}{x + 1} - \frac{2x}{x² - 1}` (ĐKXĐ : `x ne 0 ; x \ne ± 1`)
`= \frac{x²}{x(x - 1)} - \frac{x²}{x + 1} - \frac{2x}{(x - 1)(x + 1)}`
`= \frac{x²(x + 1) - x³(x - 1) - 2x²}{x(x - 1)(x + 1)}`
`= \frac{x³ + x² - x^{4} + x³ - 2x²}{x(x - 1)(x + 1)}`
`= \frac{- x^{4} + 2x³ - x²}{x(x - 1)(x + 1)}`
`= \frac{x²(-x² + 2x - 1)}{x(x - 1)(x + 1)}`
`= \frac{-²(x² - 2x + 1)}{x(x - 1)(x + 1)}`
`= \frac{-x²(x - 1)²}{x(x - 1)(x +1)}`
`= \frac{-x(x - 1)}{x + 1}`
`= \frac{x - x²}{x + 1}`
