Question

Пожалуйста помогите решить

Answer 1

Ответ:

1)

$- \frac{7a {}^{4} b {}^{3} }{3cd {}^{6} } \div ( - \frac{14ab {}^{3} }{15c {}^{4} d {}^{3} } ) = - \frac{7a {}^{4} b {}^{3} }{3cd {}^{6} } \times (- \frac{15c {}^{4}d {}^{3} }{14ab {}^{3} } ) = \frac{3a {}^{3}c {}^{3} }{2d {}^{3} }$

2)

$\frac{ 9n}{5m} - \frac{81n {}^{2} + 25m {}^{2} }{45mn} + \frac{5m - 9n}{9n} = \frac{ 81n {}^{2} - 81n {}^{2} - 25m {}^{2} + 25m {}^{2} - 45mn }{45mn} = \frac{ - 45mn}{45mn} = - 1$