Given: The function given are
[tex]\begin{gathered} f(x)=4x^3+5x^2-3x-6 \\ g(x)=4x-5 \end{gathered}[/tex]Required: To find the function-
[tex](f-g)(x)[/tex]Explanation: The function can be determined as follows-
[tex](f-g)(x)=f(x)-g(x)[/tex]Putting the values of the function f(x) and g(x)-
[tex]\begin{gathered} (f-g)(x)=(4x^3+5x^2-3x-6)-(4x-5) \\ =4x^3+5x^2-3x-6-4x+5 \\ =4x^3+5x^2-7x-1 \end{gathered}[/tex]Final Answer: Option A is correct.