[tex]\dfrac{-20v^7x^7+12v^4x^7}{4v^5x^4}=\dfrac{-20v^7x^7}{4v^5x^4}+\dfrac{12v^4x^7}{4v^5x^4}=-5v^{7-5}x^{7-4}+3v^{4-5}x^{7-4}\\\\=\boxed{3v^{-1}x^3-5v^2x^3}[/tex]
Used
[tex]\dfrac{a^n}{a^m}=a^{n-m}[/tex]
Other method:
[tex]\dfrac{-20v^7x^7+12v^4x^7}{4v^5x^4}=\dfrac{4v^4x^4(-5v^3x^3+3x^3)}{4v^4x^4(v)}=\dfrac{3x^3-5v^3x^3}{v}[/tex]
