Question

вычислите значение при x=-8

$frac{x^2 - 81}{x^3+18x^2+81x}$

Answer 1

$frac{(x - 9)(x + 9)}{x(x^2 + 18x + 81)} = frac{(x - 9)(x + 9)}{x(x + 9)^2} = frac{x - 9}{x(x+9)} = frac{-8-9}{-8(-8 + 9)} = frac{-17}{-8} = 2frac{1}{8}$