Question

Допоможіть!! Фото прикріплено ​

Answer 1

Ответ:

а)

$\frac{ac {}^{2} }{12x} + \frac{5ac {}^{2} }{12x} = \\ = \frac{ac {}^{2} + 5ac {}^{2} }{12x} = \\ = \frac{6ac {}^{2} }{12x} = \frac{ac {}^{2} }{12x}$

$\frac{ac {}^{2} }{12x} - \frac{5ac {}^{2} }{12x} = \\ = \frac{ac {}^{2} - 5ac {}^{2} }{12x} = \\ = - \frac{4ac {}^{2} }{12x} = - \frac{ac {}^{2} }{3x}$

б)

$\frac{x - 1}{x(x - 4)} + \frac{1}{4 - x} = \\ = \frac{x - 1}{x {}^{2} - 4x } + \frac{1}{4 - x} = \\ = \frac{x - 1}{x {}^{2} - 4x} + \frac{x \times 1}{x(4 - x)} = \\ = \frac{x - 1}{x {}^{2} - 4x} + \frac{4x}{4x - x {}^{2} } = \\ = \frac{x - 1}{x {}^{2} - 4x } - \frac{x}{x {}^{2} - 4x} = \\ = \frac{x - 1 - x}{x {}^{2} - 4x } = \\ = - \frac{1}{x {}^{2} - 4x }$

$\frac{x - 1}{x(x - 4)} - \frac{1}{4 - x} = \\ = \frac{x - 1}{x {}^{2} - 4x } - \frac{1}{4 - x} = \\ = \frac{x - 1}{x {}^{2} - 4x} - \frac{x \times 1}{x(4 - x)} = \\ = \frac{x - 1}{x {}^{2} - 4x} - \frac{x}{4x - x {}^{2} } = \\ = \frac{x - 1}{x {}^{2} - 4x} = \\ = \frac{x - 1}{x {}^{2} - 4x} + \frac{x}{x {}^{2} - 4x } = \\ = \frac{x - 1 + x}{x {}^{2} - 4x} = \\ = \frac{2x - 1}{x {}^{2} - 4x}$