[x-2y=-9 y-2=3 2z x=47]
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(y-z)^2+(z-x)^2+(x-y)^2=(x+y-2z)^2+(y+z-2x)^2+(z+x-2y)^2[(y-z)^2-(y+z-2x)^2]+[(z-x)^2-(x+z-2y)^2]+[(
1/x=p1/y=q1/z=rpq+qr+pr=1(y+x)/z+(y+z)/x+(z+x)/y≥2(1/x+1/y+1/z)^2为(pq+qr+pr)[r/p+r/q+q/r+q/p+p/r+p/q
x-2y=-9-------x=2y-9带入2z+x=47得,y+z=28与y-z=3联立得y=31/2,z=25/2,所以x=22y-z=32z+x=47y=2x-7--------y=2x-7带入
实数x,y,z,满足那么x+y=6,z^2=xy-9,∴xy=z^+9,(x-y)^=(x+y)^-4xy=-4z^>=0,∴z=0,(x+y)^z=6^0=1.
x+y-z=6y+z-x=2z+x-y=0三式相加得x+y+z=8-得2z=2z=1-得2x=6x=3-得2y=8y=4x=3y=4z=1
有这样的公式:a^3+b^3+c^2-3abc=(a+b+c)(a^2+b^2+c^2-ab-bc-ca)左边减右边,证明:(x+y-2z)^3+(y+z-2x)^3+(z+x-2y)^3-3(x+y
1\a4x+9y=12,b3y-2z=1,c2x+6z=3a-3b4x+6z=9与C联立x=3z=-1/2带入ay=0x=3y=0z=-1/22\a3x-y+2z=3,b2x+y-3z=11,cx+y
三式相加得4X+4Y+4Z=72X+Y+Z=18所以X=14Y=1Z=3
设a=x-y,b=y-z,-a-b=z-x(y-z)平方+(x-y)平方+(z-x)平方=(y+z-2x)平方+(z+x-2y)平方+(x+y-2z)平方b^2+a^2+(-a-b)^2=(-a-b-
思路:(x-2y+z)/9=(2x+y+3z)/10=-(3x+2y-4z)/3=1即(x-2y+z)/9=1,(2x+y+3z)/10=1,-(3x+2y-4z)/3=1即(x-2y+z)=9,(2
x+y+z=6(1)2x-y+z=3(2)3x+9y+z=24(3)(1)-(2)得:2y-x=3(4)(3)-(1)得:2x+8y=18即x+4y=9(5)(4)+(5)得:6y=12y=2代入(4
将(x+y+z)²展开有(x+y+z)²=x²+y²+z²+2xy+2xz+2yz=x²+y²+z²所以2xy+2xz+
2x+y+z=71x+2y+z=82x+y+2z=931+2+3,得x+y+z=641-4,得2x+y+z-x-y-z=7-6x=12-4,得x+2y+z-x-y-z=8-6y=23-4,得x+y+2
2x+y-3z=1,①x-2y+z=6,②3x-y+2z=9③①+③得:5x-z=10④①×2+②得:5x-5z=8⑤④-⑤得:4z=2∴z=1/2x=21/10=2.1y=-1.7
z=2x+3y-11然后代入式得到5x+5y=20可得到x+y=4得到z=-2,然后代入1和3式然后1式乘以2,3式乘以2,可得到y=1,然后代入任意一式得到x值.再问:过程再答:你敢不敢给我给分啊?
=x²(y-z)+y²(z-x)+z²(x-z+z-y)=(y-z)(x²-z²)+(z-x)(y²-z²)=(y-z)(x-z)
x-2y=-9……………………(1)y-Z=3……………………(2)2Z+x=27……………………(3)由(1)得:x=2y-9…………(4)由(2)得:z=y-3…………(5)把(4)(5)代入(3
设x/2=y/3=z/5=ax=2ay=3az=5a是不是求的是:(x+3y-z)/(x-3y+z)?若是,如下:(x+3y-z)/(x-3y+z)=(2a+9a-5a)/(2a-9a+5a)=-3
根据公式(a+b+c)^2=a^2+b^2+c^2+2ab+2bc+2ac公式展开:得到(x^2+y^2+z^2=2xy-2yz-2xz)-(x^2+y^2+z^2-2xy-2yz+2xz)合并同类项