I've been having struggles with math recently and would greatly appreciate help

ANSWER:
[tex]-4x^3+4x^2-4x+2[/tex]STEP-BY-STEP EXPLANATION:
We have the following expression:
[tex](4x^3+6x^2-9x+1)-(8x^3+2x^2-5x-1)[/tex]In order to operate, we must first break the parentheses and then group similar terms, like this:
[tex]\begin{gathered} 4x^3+6x^2-9x+1-8x^3-2x^2+5x+1 \\ (4x^3-8x^3)+(6x^2-2x^2)+(-9x+5x)+(1+1) \\ \text{ therefore:} \\ -4x^3+4x^2-4x+2 \\ (4x^3+6x^2-9x+1)-(8x^3+2x^2-5x-1)=-4x^3+4x^2-4x+2 \end{gathered}[/tex]