x+y／y=5／4,则x／y=----------------

x+y／y=5／4,则x／y=---------------- 已知x*x+4x+y*y-2y+5=0,则x*x+y*y=? 4x=5y (y不等于0).则有.y.y/x.x-y.y=? 若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y＝ 5x-4y(y-x)=? 已知：4x = 5y,求(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= （5x-6y)(x+y)=0(x不等于y),则y/x= （5x+3y)(3y-5x)-(4x-y)(4y+x)= 4(x-y)-3(x-y)=9 5(x-y)+2(x-y)=11 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 已知x/5=y/3,则(x/x+y)+(y/x-y)-(yxy/xxx-yxy) （x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x 先化简再求值(x-y)(x-2y)+(x-2y)(x-3y)-2(x-3y)(x-4y) x=4 y=5 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