X^2+Y^2-4X+Y=0 和X^2+Y^2-2Y-4=0 解方程组

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x+2y+2=0 7x-4y=-41 求x和y x*x+2x+y*y-4y+5=0 x= y= {x+2y+2=0 {7y-4y=-41 求X和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)= 先化简再求值{(x-y)(x+y)-(x+y)(x-2y)}/y 其中xy的值是代数式{(3x-2y-7)^2+|2x+3y先化简再求值{(x-y)(x+y)-(x+y)(x-2y)}/y 其中x和y的值是代数式{(3x-2y-7)^2+|2x+3y+4|}^0无意义 已知X,Y,满足(X+3Y)(X-3Y)=-10(Y^2-6/5)和2X(Y-1)+4(1/2X-1)=0 （X+Y)^2 X^2Y+XY^2注：*/* 是分数 x*x+y*y-2x+4y+5=0求x, 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? (2x-2y)/3-(x-y)=-1和6(x+y)-4(2x-y)=16 实数XY满足X*X+Y*Y+2X-4Y+1=0,求Y/（X-4）的最大值和最小值及根号下X*X+Y*Y+2X+1的最大值和最小值,需要思 5x的平方+4X-2xy+y+1=0,求x和y 解方程组3(x+y)-4(x-y)=4和(x+y)/2+(x-y)/6=1kkkkkkkk lim((x^2)y)/(x^4+y^2),x和y都趋向于0