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