Assuming $-8x^3-2y^2-10xy=0$ defines $y$ as a differentiable function of $x,$ use the theorem $\frac{dy}{dx}=-\frac{F_x}{F_y}$ to find $\frac{dy}{dx}$ at the point $(1,-1).$

$\frac{dy}{dx}{|}_{(1,-1)}|=$

$($Type an integer or a simplified fraction.$)$