1.X^2+2Y^2-4X+2=0 则X^2+Y^2的最大值2.若|X-1 |-|X-2 |>=LGA恒成立,则实数A的最大值3.若X>=1 则函数Y=X^2+1/x^2-2A（X-1/X）的最小值

若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x*x+2x+y*y-4y+5=0 x= y= x^2+6x+y^2+4x+10=0,则x+y等于多少? 已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值? 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-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 若x+y=1,x不等于0则x+(2xy+y^2)/x/(x+y)/x= 1.(x-2y)(x+2y)-(x平方+y)(x平方-y) 2.(2x-y)(y+2x)-(2y+x)(2y-x)3.已知：x+y=6,x平方-y平方=48,求x,y的值4.x平方-2x分之x+2 -- x平方-4x+4分之x-1 (x-4y)(2x+y)= 求y=(x^2)+2x(x≥0) y=-x+2x(x x^2+y^2-2x+4y-20=0则y/x的最大值,x+y的最大值 设实数x,y 满足x²+4y²+2x-4y+2+0 则x+y= 如果有理数x.y满足x^2+y^2+4x-6y+13=0,则y^x=? x*x+y*y-2x+4y+5=0求x, 若x,y,z成等差数列,则(z-x)^2-4(x-y)(y-x)= 已知3x-4y=0,则x^2-y^2/x^2+y^2