请你说明(4x^3+8x^2-6x-1)+(1.5x^3-4.2x^2+3.7x-6)-(3.8x^2-2.3x+5.5x^3+1_数学解答

请你说明(4x^3+8x^2-6x-1)+(1.5x^3-4.2x^2+3.7x-6)-(3.8x^2-2.3x+5.5x^3+15)的值
我去他题都会,就在这道题晕菜了啊,

人气：391 ℃　时间：2019-11-24 16:15:51

解答

(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