Step $1$

Assume that all fractions in the given product are defined.

Before multiplying the fractions, we factor their numerators and denominators, becau needed for simplification.

$\frac{x^2-3x-4}{x^2-8x+7}*\frac{x^2-x-42}{x^3-4x^2}*\frac{x-x^3}{x^2-2x+1}$

First, factor each numerator and denominator. Simplify your answers completely.

$x^2-3x-4=(x+1)()$

$($:$x^2-8x+7=(x-1)(,]\}$