Question

Решите уравнение lg(x^-2x)=lg(8)

Answer 1

$lg(x^2-2x) = lg(8)$
$x^2-2x = 8$
$x^2-2x-8 = 0$
$D = sqrt{(-2)^2-4*1*(-8)} = sqrt{4+32} = sqrt{36} =6$
$x_1 = frac{2+6}{2} =4$
$x_2 = frac{2-6}{2} =-2$