The given polynomial is:
[tex]4x^7-20x^6+8x^5[/tex]Notice that the greatest common factor of the numbers 4, 20, and 8 is 4.
Also, notice that the greatest common factor of the variables is x⁵.
Hence, the greatest common factor of the polynomial is 4x⁵.
Therefore factor out 4x⁵ from the polynomial to get:
[tex]\begin{gathered} 4x^7-20x^6+8x^5=4x^5(\frac{4x^7}{4x^5}-\frac{20x^6}{4x^5}+\frac{8x^5}{4x^5}) \\ =4x^5(x^2-5x+8) \end{gathered}[/tex]