Respuesta :

Simplify the given expression as shown below

[tex]\begin{gathered} 3x(4x^4-5x)=3x*4x^4+3x(-5x)=12x^5+(-15x^2) \\ =12x^5-15x^2 \end{gathered}[/tex]

Therefore, the answer is 12x^5-15x^2