x-y+2=0,4x^2-y^2=12,怎么解

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 (X,Y) f(x,y)={12y^2,0 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 x*x+2x+y*y-4y+5=0 x= y= 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 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= (x-4y)(2x+y)= 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） 求x ,y 9x^2+4y^2-12x-8y+8=0 x²+4y²-2x+12y+10=0求X,Y值 若x.y满足条件2x+y-12=0,x-4y+10 先化简再求值; 解方程组 x(x-y)-y(x+y)+2xy 其中x=2 ,y=-22.x[x-x(x-1)],其中x=-2解方程组4x+3y=12x-y=32.y+1=2x 4x-y=2 3.2x+2y=0 2x-y+24=0 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? x*x+y*y-2x+4y+5=0求x, 已知x^2+y^2+13-4x+6y=0,求(2x-y)^2-2(2x-y)(x+2y)+(x+2y)^2 已知2x-y/x+3y=2,求代数式4x-2y/x+3y减4x+12y除以2x-y