Answer
$$\frac{2x^2-2x}{x+1}$$
Work Step by Step
Recall, one never divides by a fraction. Rather, if we want to divide by a fraction, we multiply by the reciprocal of the fraction. Recall, the reciprocal of a fraction is that fraction with the numerator and the denominator switched. Thus, we find:
$$ \frac{4x^4}{x^2-1}\times \frac{x^2-2x+1}{2x^3}\\ \frac{2x\left(x-1\right)^2}{\left(x+1\right)\left(x-1\right)}\\ \frac{2x\left(x-1\right)}{x+1}\\ \frac{2x^2-2x}{x+1}$$