Question

прошу помогите с подробным решением ​

Answer 1

Объяснение:

5.

$\frac{b - 4}{b - 5} \times \frac{b {}^{2} - 25}{4b - b {}^{2} } = \frac{b - 4}{b - 3} \times \frac{b {}^{2} - 25}{b(4 - b)} = \frac{b - 4}{b - 3} \times \frac{b {}^{2} - 25 }{b( - (b - 4))} = \frac{ - 1}{b - 3} \times \frac{b {}^{2} - 25 }{b} = - \frac{b {}^{2} - 25 }{b(b - 3)} = \frac{25 - b {}^{2} }{b {}^{2} - 3b }$

6.

$\frac{4x {}^{2} }{x - 3} - 4x = \frac{4x {}^{2} - 4x (x - 3) }{x - 3} = \frac{4x {}^{2} - 4x {}^{2} + 12x}{x - 3} = \frac{12x}{x - 3}$