1（3X^2+2XY-1/2X)-(2X^2-XY+x)2 (1/2XY+Y^2+1)+(X^2-1/2XY-2Y^2-1)3 -_数学解答

1（3X^2+2XY-1/2X)-(2X^2-XY+x)
2 (1/2XY+Y^2+1)+(X^2-1/2XY-2Y^2-1)
3 -(X^2Y+3XY-4)+3(X^2Y-XY+2)
4 -1/4(2K^3+4K^2-28)+1/2(K^3-2K^2+4K)

人气：107 ℃　时间：2020-04-08 07:21:20

解答

(3x^2+2xy-1/2x)-(2x^2-xy+x)=3x^2+2xy-1/2x-2x^2+xy-x=3x^2-2x^2+2xy+xy-1/2x-x=x^2+3xy-3/2x（1/2xy+y^2+1)+(x^2-1/2xy-2y^2-1) =1/2xy-1/2xy+y^2+1+x^2-2y^2-1=x^2-y^2.-(x^2y+3xy-4)+3(x^2y-xy+2) =-x^2y-3xy+4+...