Question

Найдите значение выражения а^2-81b^2\9ab:(1\9b-1\a) при а=2 8/17, b=9 1/17

Answer 1

$\frac{a^2-81b^2}{9ab} : ( \frac{1}{9b} - \frac{1}{a} ) = \frac{(a-9b)(a+9b)}{9ab}: ( \frac{a-9b}{9ab} ) = \\ \\ = \frac{(a-9b)(a+9b)}{9ab} * \frac{9ab}{a-9b} = a+9b$

 $a= 2 \frac{8}{17} \\ \\ b=9 \frac{1}{17} \\ \\ 2 \frac{8}{17} + 9 * 9 \frac{1}{17} = 2 \frac{8}{17}+ \frac{9*154}{1*17} = 2 \frac{8}{17} + 81 \frac{9}{17} = 84$