To determine the factor of the given polynomial, first, we rewrite it as follows:
[tex](16x^2+4x)+(-20x-5).[/tex]Now, notice that:
[tex]\begin{gathered} 16x^2+4x=4x(4x^+1), \\ -20x-5=-5(4x+1). \end{gathered}[/tex]Factoring out the 4x+1, we get:
[tex](16x^2+4x)+(-20x-5)=(4x-5)(4x+1).[/tex]