作业帮X^3+Y^4+Z^5=20,X^5+Y^6+Z^7=30,X^7+Y^8+Z^9=40,求各未知数
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X^3+Y^4+Z^5=20,X^5+Y^6+Z^7=30,X^7+Y^8+Z^9=40,求各未知数
X^3+Y^4+Z^5=20,X^5+Y^6+Z^7=30,X^7+Y^8+Z^9=40,求各未知数
X^3+Y^4+Z^5=20,X^5+Y^6+Z^7=30,X^7+Y^8+Z^9=40,求各未知数
因为x^3+x^7>=2√(x^3*x^7)=2x^5
y^4+y^8>=2y^6
z^5+z^9>=2z^7
所以x^3+y^4+z^5+x^7+y^8+z^9>=2(x^5+y^6+z^7)
而x^3+y^4+z^5+x^7+y^8+z^9=60=2(x^5+y^6+z^7)
所以不等式x^3+x^7>=2x^5,y^4+y^8>=2y^6,z^5+z^9>=2z^7均取等号
所以x^3=x^7,y^4=y^8,z^5=z^9,
个人认为方程组无解
(4x-2y-z)-{5x-[8y-2z-(x-2y)]-x-(3y-10z)}=?
(x+y):(y+z):(z+x)=3:4:5 3x+y-z=-4已知(x+y):(y+z):(z+x)=3:4:5 ；3x+y-z=-4求x y z
(4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuaihuajian
设|x|-|y|+|z|=|x+y+z|,且|x+y|=4,|y+z|=5,|y|=3,求(x-y-z)^2的值
x+y=5 2x+3y-z=9 x-y+z=4
已知3X=4X,5Y=6Z求X+Y：Y+Z
(4x-2y-z)-{5x-[8y-2z-(x+y)]-2(3y-10z)}=?好难啊
x+y-z=3 y+z-x=5 z+x-y=7 求x,y,z
x/2=y/3=z/5 x+3y-z/x-3y+z
一只x/3=y/4=z/5,求x+y+z/x及x+y+z/x-y+z的值
X:Y=3:4,Y:Z=6:5=X:Y:Z=( ):( ):( )
已知：4x-5y+2z=0 x+4y-3z=0则：(x*x+y*y+z*z)/(x*y+y*z+z*x)=____.
x:y=3:2 y:z=5:4 x+y+z=66
x:y=3:2 y:z=5:4 x+y+z=66
{x:y=2:3 y:z=4:5 x+y+z=35
x:y=2:3 y:z=4:5 x+y+z=35
x+y+z=111,y:x=3:2,y:z=5:4
3x=4y 2y=5z 试求x:y:z