3x^2y-(6xy-2(4xy-2)-x^2y)+1,其中x=-2分之1我没有漏了y等于几.结果等于-3 怎么算的已知代数式ax的5次+bx的三次+3x+c 当x=0时。值为-1（1）c=？(2)当x=3时，值为9，x=-3 值为？（3）在第三小题的已知条件

xy-2{xy-[3x^2y-(4xy^2+0.5xy)]+4x^2y}+6xy^2 （X-3xy+4xy-y）-[-2x-2（xy-3/2xy）-y]+6xy的过程 5x^3y*(-3y)^2+(-6xy)^2*(-xy)+xy^3*(-4x^2) 已知1/x-1/y=2,求3x+7xy-3y/2x-3xy-2y答案是1/x-1/y=2(y-x)/xy=2 得：x-y=-2xy(3x+7xy-3y)/(2x-3xy-2y)=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy)=xy/(-7xy)=-1/7 谁能帮我解释一下=[3(x-y)+7xy]/[2(x-y)-3xy]=(-6xy+7xy)/(-4xy-3xy) 是怎 3xy(x^2y-xy^2+xy)-xy^2(2x^2-6xy+2x)过程 x^2-xy-6y^2+3xy+y+2 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 2x²y-3(2xy-xy)-xy 诺x+y=6,xy=4 求(5x-4y-3xy)-(8x-y+2xy) （-3x^y+2xy)-( )=4x^+xy 化简：3x^2-[5xy-(x^y-3xy)+4x^2y-8xy] (-3xy+2xy)-(4xy+xy) x^+2xy+y^+4=16 x^-2xy+y^=16 求(3xy+6y^)+|x^-(2xy+2y^-3x^)|的值 4xy-[(x²+5xy-y²)-(3xy-1/2y)]x=3,y=-6 x^3y(-4y)^2+(-7xy)^2*(-xy)-5xy^3*(-3x)^2 3(x^2y+xy)-4(xy-2x^2y)-(-xy) 1-2/x+y=xy,4y+6x=xy.求xy的解? 当x-y=2xy时,求4x-3xy-4y/xy