+y^2-1)^2=4 求X^2+Y^2的值应该大家都知道吧..^2 就是平方的意思对了X^2+Y^2 是不是还叫什么定理之类的?我都忘记了..

已知:【(x²+y²)-(x-y)²+2y(x-y)】/4y=1,求4x/4x²-y²-1/2x+y 已知x-y=1,求[(x+2y)^2+(2x+y)(x-4y)-3(x+y)(x-y)]除以y的值大神们帮帮忙 已知x-y=1,求[(x+2y)²+(2x+y)(x-4y)-3(x+y)(x-y)]÷y的值 2x-y=2,求[(x²+y²)-(x-y)²+2y(x-y)]÷4y x+2y=2x+y+1=7x-y 求：2x-y? 如果|X|=4 |Y|=2 且|X+Y|=X+Y 求X+Y (x-y)/(x+y)=3求( 3x-2y-1)/(x+y-5) 若x*x+y*y=x+y-1/2,求x,y的值如题 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 若2/x-1/y=3,求[y/x-y/x-y(x-y/x-x+y)]/x-2y/x的值 4/X+1/Y=2,XY=-1,求代数式4Y-X/X-2Y/（x+2y-12Y²/x-2y)的值 已知 x-2y=-2 求(2y-x)平方-2x+4y-1 x^2-x+y^2+2y+5/4=0 求x^-1+y^0 已知2y-x=-3,求[4y(2x-y)-2x(2x-y)]/(2x-y 4x-3y=5 x^2+y^2=1 求x,y 3x+4y-5=0 x^2+y^2=1求x.y 2x+4y=3 -3x-2y=1 ..求x和y 已知3x-4y/2x+y=1/2 求x/y的值