(3/2x2-5xy+y3)-【-3xy+2(1/4x2-xy)+2/3y2】,其中/x-1/+(y+2)2=0

(3/2x2-5xy+y3)-【-3xy+2(1/4x2-xy)+2/3y2】,其中/x-1/+(y+2)2=0 化简求值:3(x2+xy)-2(x3-y3-3xy)+(-3xy-2y3),其中x=1,y=2 x3-y3-x2+2xy-y2 因式分解 已知:x+y=5,xy=3,x3+y3=(x+y)(x2-xy+y2),求x3分之1加上y3分之1 当K=什么时,多项式2x2次方减4xy+3y3次方与3kxy+5的和中不含XY项 x3-y3-x2+2xy-y2 因式分解还有：(2) x2+2xy-3y2+3x+y+2(3) 6x2-7x-4（实数范围内） 已知x2-3xy=-5,xy+y2=3,求x2-2xy+y2. 2(x2-xy)-3(2x2-3xy)-2[x2-(2x2-xy+y2)] 化简. 4x2-3y2+2xy-4x2+5x2 (3xy-9x2-2y2-6xy)-(6x2+2xy-3xy-y) A=x3 -2y3 +3x2 y+xy2 -3xy+4.B=y3-x3 -4x2 y-3xy-3xy2+3 C=y3 +x2 y+2xy2 +6xy 试说明x、y的值对A+B+C无关 5x2*3xy= -（x2-2xy-y2)+(5x2-2xy-3y2)-（x2-2xy-y2)+(5x2-2xy-3y2)化简 2(x-xy)-3(2x2-3xy）2[x2（2x2-xy+y2)] (-3xy+2xy)-(4xy+xy) 多项式x2-3xy+2y2-2加上( )等于5x2-7xy-3y2 解方程组 x2 -2xy -y2 =1 2x2 -5xy -3y2 =0 已知x2+xy=3,xy+y2=-2,则2x2-xy-3y2=