若5x=0.8y,则x:y=( ):( )

若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y＝ 若5x=0.8y,则x:y=( ):( ) 若3x=5y,则x:y=________,(x-y):y=______ 若3x-5y=0,则x+y/x=（）,x-y/y=（）,2x-3y/2x+3y=( ) (5)若x/2=y/3(y不为0）则x/y=____,x+y/y=___,y/x-y=___. x+y／y=5／4,则x／y=---------------- 若f(x+y,y/x)=x^2-y^2,则F(X,Y)= （5x-6y)(x+y)=0(x不等于y),则y/x= 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 若x-y=3,则-x+5+y=( ) 已知x/5=y/3,则(x/x+y)+(y/x-y)-(yxy/xxx-yxy) 若2x-5y=0,则y：x 若5x-4y=6,4x-5y=8,则x+y=( ),x-y=( ) 若5x+3y=3x+4y=x+2y+6,则x+y=___ 若8x=5y,则y除以x= 多少,x+y除以x-y=多少? 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 若正实数x,y满足x+y+1/x+1/y=5,则x+y的最大值是多少 若【x+y=5,2x+y=8】,则x+2y=