整理后:
x^3 + 5x^2 + 4x - 3 - 2x^3 + x^2 +3x + 1 + x^3 - 6x^2 - 7x + 4
= 0x^3 + 0x^2 + 0x + ( -3 + 1 + 4)
= 2
希望对你有所帮助