Question

срочно!!! помогите ​

Answer 1

Ответ:

№5.

$\frac{15x + 3 {x}^{2} }{6 {x}^{2} - tx } = \frac{x(15 + 3x)}{x(6x - t)} = \frac{15 + 3x}{6x - t}$

№6.

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

№7

$\frac{7 {x}^{2} - 3 }{7x + 4} = x - 1 \\ \frac{7 {x}^{2} - 3 }{7x + 4} - \frac{x(7 x + 4)}{7x + 4} = - 1 \\ \frac{7 {x}^{2} - 3 - 7 {x}^{2} - 4x }{7x + 4} = - 1 \\ \frac{4x + 3}{7x + 4} = 1 \\ 4x + 3 = 7x + 4 \\ 4x - 7x = 4 - 3 \\ - 3x = 1 \\ x = - \frac{1}{3}$