Y=X^2(2-5X),(0

x*x+2x+y*y-4y+5=0 x= y= 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=? 先化简,再求值 [2/3x - 2/x+y（x+y/3x -x-y）]*x/x-y,其中5x+3y=0 先化简,再求值:[3x-2/x+y(x+y/3x-x-y)]/(x-y/x),其中5x+3y=0 x*x+y*y-2x+4y+5=0求x, x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 若2x-3y+4=0则x（x*x-1)+x(5-x*x)-6y+7 .先化简再求值：（2x+y）（2x+y)-(2x-y)平方其中X,Y满足X平方+Y平方-2X+4Y+5=0 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) 已知X.x+y.y-4x+2y+5=0,求4X.X-12X Y+9Y.y的值 {x+y=1 ,xy=-6{x(2x-3)=0,y=x²-1{(3x+4y-3)(3x+4y+3)=0,3x+2y=5{(x-y+2)(x+y)=0,x²+y²=8{(x+y)((x+y-1)=0,(x-y)(x-y-1)=0 2x-5y=0,y/x=为什么 已知7x+5y/2y-x=3/2,且x≠0,求X/x-4y 若2x-5y=0,则y：x x*x+4y*y+2x*x-4y+2=0求根号下5x*x+16y*y的值快啊 求y=(x^2)+2x(x≥0) y=-x+2x(x