X+Y=10 XY/2=12 X=4 Y=6 第三步怎么来的.

|x|/x+y/|y|+xy/|xy|= X×X-2XY-Y×Y+2X-2Y+2=02X×2X-4XY-2Y×2Y+3X-3Y+4=0X×X+2XY+Y×Y+X+Y-56=0X×X-2XY+Y×Y-X+Y-12=0X×X-3XY+Y×Y=-13X×3X-XY+3Y×3Y=13 两个在一起的方程之间有所联系（要求一步一步写出来） 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 化简:(x+y-4xy/x+y)*(x-y-4xy/x-y)= 若x+y=4,x^3+y^3=(x+y)(x^2-xy+y^2)z,求x^3+12xy+y^3的值. （-3x^y+2xy)-( )=4x^+xy 计算：[(x-y)^2-(x+y)^2]/(-4xy)= 2x^+xy-y^-4x+5y-6=? (x+y)^2/y^2-xy÷[-y^2+xy/(x-y)^2,x=0,y=根号10 解方程组：(x+y)^2-2xy-(x^2)(y^2),x+y-xy=4解方程组(x+y)^2-2xy-(x^2)(y^2)=10x+y-xy=4 （12x^2y-8xy^2+16xy）/-3x+2y-4=? (12x^2y-8xy^2+16xy）/-3x+2y-4=? x^2+xy=12,xy+y^2=15,求(x+y)^2-(x+y)(x-y) 已知X+Y=3,XY=-1,求2(X-Y)^4-9(X-Y)^2+12XY 若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*y)的值 已知x+y=-2,求代数式(6xy+10y)+[4x-2(3xy+2y-x)] 已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² 1-2/x+y=xy,4y+6x=xy.求xy的解?