[tex]\text{Designando como} \ y \ \text{o polin} \hat{o} \text{mio a ser descoberto, temos:} \\\\ 4x^2 \cdot y = 8x^5 + 16x^4 - 20x^3 \\\\ y = \frac{8x^5 + 16x^4 - 20x^3}{4x^2} \\\\ y = \frac{4x^2 \cdot (2x^3 + 4x^2 - 5x)}{4x^2} \\\\ y = \frac{\not{4x^2} \cdot (2x^3 + 4x^2 - 5x)}{\not{4x^2}} \\\\ \boxed{y = 2x^3 + 4x^2 - 5x}[/tex]
