已知x,y都是正数,求证:(x+y)(x^+y^)(x^3+y^3)≥8x^3y^3
已知x,y,z都是正数,且xyz=1,求证:x^2/(y+z)+y^2/(x+z)+z^2/(x+y)≥3/2
已知xy都是正数,求证(x+y)(x的平方+y的平方)(x的3次方+y的3次方)大于等于8x的3次方y的3次方
已知x,y,z都是正数, 且x^3+y^3+z^3=3xyz, 求证:x=y=z.
已知x,y,z都是正数,且3^x=4^y=6^z 求证 1/z-1/x=1/2y
已知xy都是正数,若x+2y=3,求1/x+2/y最小值
已知正数x,y
已知X-Y/X+Y=3,求代数式2(x-y)/X+Y-3X+Y/X+Y
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
已知:3x=8y.求(1)x+y/y (2)2x+3y/x-2y
1.((y+2x)(-2x+y)+4(x+2y)^2)/3y 2.(2(x-y)^3-8(x-y)^2(x+y)+6y(
设x.y.z满足3x=4y=6z(x.y.z都是指数)求证
已知x/5=y/3,则(x/x+y)+(y/x-y)-(yxy/xxx-yxy)