求y=(x+4)(128/x+2)-128 (x>0)的最值 运用导数知识解

已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y除以2x-y 已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y/2x-y的值 已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y/2x-y的值 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 x^2+y^2+4x-6y+12=0.求x^y的值 求x ,y 9x^2+4y^2-12x-8y+8=0 x²+4y²-2x+12y+10=0求X,Y值 如果|X|=4 |Y|=2 且|X+Y|=X+Y 求X+Y 4/X+1/Y=2,XY=-1,求代数式4Y-X/X-2Y/（x+2y-12Y²/x-2y)的值 已知2y-x=-3,求[4y(2x-y)-2x(2x-y)]/(2x-y 已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 求x²+y²-2x+4y+1的最小值 求x,y的值 x²+2xy+4x-12y+22=0 x*x+y*y-2x+4y+5=0求x, 若x+y=4,x^3+y^3=(x+y)(x^2-xy+y^2)z,求x^3+12xy+y^3的值. 2x-y=2,求[(x²+y²)-(x-y)²+2y(x-y)]÷4y 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 x^2+2y^2+4x-12y+22=0求x,y2x^2