Answer:[tex]\begin{gathered} \mleft(8x^4+6x^3-4x^2-2\mright)-\mleft(3x^4-5x^2-7x+9\mright) \\ \\ =5x^4+6x^3+x^2+7x-11 \end{gathered}[/tex]
Explanation:[tex]\begin{gathered} (8x^4+6x^3-4x^2-2)-(3x^4-5x^2-7x+9) \\ \\ =8x^4-3x^4+6x^3-4x^2+5x^2+7x-2-9 \\ \\ =5x^4+6x^3+x^2+7x-11 \end{gathered}[/tex]
