x*y=(x-4)(y+2)如何化简为x=2y+4

x*y=(x-4)(y+2)如何化简为x=2y+4 请问如何化简(4x-y)/x^2y^2 - (x+y)/xy^3 -6(8x-3y)-(-4x+3y)+2如何化简?其中X=325 Y=175 化简求值：2(x+y)(x-2y)-2x(x+y),其中x、y满足x^2+y^2-2x+4y=-5 化简求值:[(x+y)(x-y)-(x-y)²+2y(x-y)]÷4y,其中x=二分之一,y=2 化简求值:[(x+y)(x-y)-(x-y)²+2y(x-y)]÷4y,其中x=二分之一,y=2 如何化简x²+y²+2xy 结果为（x+y)² 如何化简(x+y+z)(x+y-z)(x-y+z)(-x+y+z) 已知x>0,Y>0,如何证x^2/y+y^2/x>=x+y (x+y)(x+2y)(x+3y)(x+4y)=-40y的值为根号11 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 如何证明y=f(x)=2x^2+4x为减函数 如何证明y=f(x)=2x^2+4x为减函数? 化简求值：已知x、y满足：x^2+y^2-4x+6y+13=0 求代数式 的值.(3x+y)^2-3(3x-y)(x+y)-(x-3y)(x+3y)急用！ 化简求值{(x=2y)(5x-2y)-(3x+2y)(3x-2y)]/4x,其中x=2,y=-1 初二化简求值题[（5x+2y)(3x+2y)+(x+2y)(x-2y)]/4x,其中x=2,y=3 3(x-y)-2(x+y)-5(x-y)+4(x+y)+3(x-y) 化简合并同类项 (x+y)(x-2y)(x²-4y²) 其中x=8 y=-8 化简求值