Question

алгебра 8 класс срочно!!! ​

Answer 1

Ответ:

Объяснение:

см.рисунок

Answer 2

Объяснение:

а)

$( \frac{x + 3y}{x - 3y} + \frac{x - 3y}{x + 3y} ) \times \frac{x {}^{2} - 9y {}^{2} }{x {}^{2} + 9y {}^{2} } =\left(\frac{\left(x+3y\right)\left(x+3y\right)}{\left(x-3y\right)\left(x+3y\right)}+\frac{\left(x-3y\right)\left(x-3y\right)}{\left(x-3y\right)\left(x+3y\right)}\right)\times \left(\frac{x^{2}-9y^{2}}{x^{2}+9y^{2}}\right) =\frac{\left(x+3y\right)\left(x+3y\right)+\left(x-3y\right)\left(x-3y\right)}{\left(x-3y\right)\left(x+3y\right)}\times \left(\frac{x^{2}-9y^{2}}{x^{2}+9y^{2}}\right) =\frac{x^{2}+3xy+3xy+9y^{2}+x^{2}-3xy-3xy+9y^{2}}{\left(x-3y\right)\left(x+3y\right)}\times \left(\frac{x^{2}-9y^{2}}{x^{2}+9y^{2}}\right) =\frac{2x^{2}+18y^{2}}{\left(x-3y\right)\left(x+3y\right)}\times \left(\frac{x^{2}-9y^{2}}{x^{2}+9y^{2}}\right) =\frac{\left(2x^{2}+18y^{2}\right)\left(x^{2}-9y^{2}\right)}{\left(x-3y\right)\left(x+3y\right)\left(x^{2}+9y^{2}\right)} =\frac{2\left(x-3y\right)\left(x+3y\right)\left(x^{2}+9y^{2}\right)}{\left(x-3y\right)\left(x+3y\right)\left(x^{2}+9y^{2}\right)} =2$

б)

$( \frac{3a - 2}{3a + 2} - \frac{3a + 2}{3a - 2} ) \div \frac{8a {}^{2} }{3a - 2} =\frac{\frac{\left(3a-2\right)\left(3a-2\right)}{\left(3a-2\right)\left(3a+2\right)}-\frac{\left(3a+2\right)\left(3a+2\right)}{\left(3a-2\right)\left(3a+2\right)}}{\frac{8a^{2}}{3a-2}} =\frac{\frac{\left(3a-2\right)\left(3a-2\right)-\left(3a+2\right)\left(3a+2\right)}{\left(3a-2\right)\left(3a+2\right)}}{\frac{8a^{2}}{3a-2}} =\frac{\frac{9a^{2}-6a-6a+4-9a^{2}-6a-6a-4}{\left(3a-2\right)\left(3a+2\right)}}{\frac{8a^{2}}{3a-2}} =\frac{\frac{-24a}{\left(3a-2\right)\left(3a+2\right)}}{\frac{8a^{2}}{3a-2}} =\frac{-24a\left(3a-2\right)}{\left(3a-2\right)\left(3a+2\right)\times 8a^{2}} =\frac{-3}{a\left(3a+2\right)} =\frac{-3}{3a^{2}+2a}$