Question

найдите значение выражения (x²/x²-9xy):(x/x²-81y²) при x=7+9√7, y=9-√7

Answer 1

$\frac{ x^{2} }{ x^{2} -9xy}: \frac{x}{ x^{2} -81 y^{2} } = \frac{ x^{2} }{x(x-9y)}* \frac{(x-9y)(x+9y)}{x}=x+9y\\\\7+9 \sqrt{7}+9*(9- \sqrt{7} )=7+9 \sqrt{7}+81-9 \sqrt{7} =88$