(4x^3+8x^2-6x-1)+(1.5x^3-4.2x^2+3.7x-6)-(3.8x^2-2.3x+5.5x^3+15)=4x^3+8x^2-6x-1+1.5x^3-4.2x^2+3.7x-6-3.8x^2+2.3x-5.5x^3-15=(4x^3+1.5x^3-5.5x^3)+(8x^2-4.2x^2-3.8x^2)+(3.7x-6x+2.3x)-1-6-15=0+0+0-22=-22可不可以简单些(4x³+8x²-6x-1)+(1.5x³-4.2x²+3.7x-6)-(3.8x²-2.3x+5.5x³+15) =4x^3+8x²-6x-1+1.5x³-4.2x²+3.7x-6-3.8x²+2.3x-5.5x³-15 =(4+1.5-5.5)x³ +(8-4.2-3.8)x² +(3.7-6+2.3)x-1-6-15 =0+0+0-22 =-22