A=2x^2-3xy+y^2+x-3y,B=4x^2-6xy+2y^2+4x-y,若｜x-3a|+(y+3)^2=0,且B-2A=a,求A的值．

x*x+xy=3,xy+y*y=2,则x*x+2xy+y*y=________? (-x+2y)(2x+y)-(2x+y)(y-2x)-3xy=?因式分解 x+y=-3 xy+x+y=-2 x/y+y/x=? 因式分解:12xy^2(y-x)+xy^3(x-y)+4x^2y(x-y) f(xy,x-y)=x^2+3xy+y^2,则f(x,y)=? 若1/x-1/y=2,求3x-2xy-3y/x-xy-y的值3x-2xy-3y/x-xy-y 不好意思，是3x-2xy-3y/x-2xy-y 已知：A=X*X-3xy+y*y,B=2x*x+xy-3y*3y.求A+B,A-B,A+2B （-3x^y+2xy)-( )=4x^+xy (x^3-2x^2+xy^2)/(x-y)+(x+y)(y-x)=? X^Y-2XY^2+y^3 x-y/xy=( )/x^3y^2 已知xy=-2,x-y=3,求（x+y)（x-y)-y^2+（x-y)^2-（6x^2y-2xy^2)÷2y a/x-y,b/3y-3x,c/x^2-2xy+y^2通分 如果x/x-y=a,则分式2x^2y-2xy^2/3x^2y x^2-4xy+3y^2=（x-3y)(x-y)x^2-4xy+3y^2 怎么分解成（x-3y)(x-y) 当x-y=2xy时,求4x-3xy-4y/xy x-y/x+y=-1/2,x*x-xy-2y*y/x*x-3xy+2y*y的解是多少?同上,请将过程写出, 已知X+Y=3XY,求2X+2Y-XY除以X+Y+2XY的值,要算理.已知X+Y=3XY,求2X+2Y-XY除以X+Y+2XY的值,要算理.