Answer :
[tex] \to \sf(3x^3-4-3x) - (-8+2x^3)[/tex]
[tex] \to \sf(3x^3-4-3x) + 8 - 2x^3[/tex]
[tex] \to \sf3x^3-4-3x + 8 - 2x^3[/tex]
[tex] \to \sf3x^3 - 2x^3-3x +4[/tex]
[tex] \to \sf x^3-3x +4[/tex]
[tex] \to \sf(3x^3-4-3x) - (-8+2x^3)[/tex]
[tex] \to \sf(3x^3-4-3x) + 8 - 2x^3[/tex]
[tex] \to \sf3x^3-4-3x + 8 - 2x^3[/tex]
[tex] \to \sf3x^3 - 2x^3-3x +4[/tex]
[tex] \to \sf x^3-3x +4[/tex]