6x+7y-6y-5xy+3xy-3x 其中x=3,y=2.（化简后求值）

已知x-y=3xy,且xy不等于0,则-3x+6xy+3y/(7x-5y)-9xy-(3x-y) 因式分解 x-xy+3y-3x 2x+xy-y-4x+5y-6 5x^3y*(-3y)^2+(-6xy)^2*(-xy)+xy^3*(-4x^2) 1、(-7x^y)(2x^y-3xy^3+xy) 2、((x-y)^6)/((y-x)^3)/(x-y) 已知X+Y=6,xy=3求代数式（5XY+4X+7Y)+(6X-3XY)-(4XY-3Y)的值 x-y=3,xy=5,求代数式（7xy+4x-7y）+(6x-3xy)-(3y+4xy)的值快 已知x+y=3,xy=1,求代数式5xy+4x+7y+6x-3xy-4xy+3y的值. x+y=8,xy=-2,求(5xy+4x+7y)+(6x-3xy)-(4xy-3y)的值 3xy+xy+3+4xy-7化简,已知x=5,y=6 x^2-xy-6y^2+3xy+y+2 诺x+y=6,xy=4 求(5x-4y-3xy)-(8x-y+2xy) 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 3(x-y)²-7(x-y)+8(x-y)²+6(x-y)求详细过程（2） 5xy-4x²y-8xy²+3xy-xy²+4x²y （X-3xy+4xy-y）-[-2x-2（xy-3/2xy）-y]+6xy的过程 xy-2{xy-[3x^2y-(4xy^2+0.5xy)]+4x^2y}+6xy^2 【x(xy-xy)-y(x-xy)】÷3xy 4xy-[(x²+5xy-y²)-(3xy-1/2y)]x=3,y=-6 (x-2xy)*(-xy+2y*y)-(3x*x-2xy)(x-9xy+6y*y)答案应为-2x-x*x-3x，