Answer
$(0$, infinity)
Work Step by Step
$\frac{x}{x-10} < 0$
Denominator is zero when $x=10$
$x/(x-10) =0$
$x*(x-10)/(x-10) =0*(x-10)$
$x = 0$
(-infinity, $0)$
$(0$, infinity)
Let $x=-1$, $x=1$
$x=-1$
$\frac{x}{x-10} < 0$
$\frac{-1}{-1-10} < 0$
$-1 /-11 <0$
$1/11 < 0$ (false)
$x=1$
$\frac{x}{x-10} < 0$
$\frac{1}{1-10} < 0$
$1/-9 < 0$
$-1/9 < 0$ (true)