The given expression is,
[tex]4x(8x^4-9x^2-4x)[/tex]Multiply using distributive property(A(B+C)=AB+AC),
[tex]\begin{gathered} 4x\times8x^4-4x\times9x^2-4x\times4x \\ =32x^{1+4}-36x^{1+2}-16x^{1+1} \\ =32x^5-36x^3-16x^2 \end{gathered}[/tex]Therefore, the final expression is,
[tex]32x^5-36x^3-16x^2[/tex]