已知x^2+4y^2-4x+4y+5=0,求(2x^2+xy-y^2分之x^4-y^4)乘以(xy-y^2分之2x-y)÷(y分之x^2+y^2)^2的值已知xyz≠0,x+3y+7z=0,3x-4y-18z=0,求(x^2+2y^2+8z^2)分之(3x^2+5y^2+6z^2)的值
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![已知x^2+4y^2-4x+4y+5=0,求(2x^2+xy-y^2分之x^4-y^4)乘以(xy-y^2分之2x-y)÷(y分之x^2+y^2)^2的值已知xyz≠0,x+3y+7z=0,3x-4y-18z=0,求(x^2+2y^2+8z^2)分之(3x^2+5y^2+6z^2)的值](/uploads/image/z/3986518-22-8.jpg?t=%E5%B7%B2%E7%9F%A5x%5E2%2B4y%5E2-4x%2B4y%2B5%3D0%2C%E6%B1%82%282x%5E2%2Bxy-y%5E2%E5%88%86%E4%B9%8Bx%5E4-y%5E4%29%E4%B9%98%E4%BB%A5%EF%BC%88xy-y%5E2%E5%88%86%E4%B9%8B2x-y%29%C3%B7%EF%BC%88y%E5%88%86%E4%B9%8Bx%5E2%2By%5E2%29%5E2%E7%9A%84%E5%80%BC%E5%B7%B2%E7%9F%A5xyz%E2%89%A00%2Cx%2B3y%2B7z%3D0%2C3x-4y-18z%3D0%2C%E6%B1%82%28x%5E2%2B2y%5E2%2B8z%5E2%29%E5%88%86%E4%B9%8B%EF%BC%883x%5E2%2B5y%5E2%2B6z%5E2%29%E7%9A%84%E5%80%BC)
已知x^2+4y^2-4x+4y+5=0,求(2x^2+xy-y^2分之x^4-y^4)乘以(xy-y^2分之2x-y)÷(y分之x^2+y^2)^2的值已知xyz≠0,x+3y+7z=0,3x-4y-18z=0,求(x^2+2y^2+8z^2)分之(3x^2+5y^2+6z^2)的值
已知x^2+4y^2-4x+4y+5=0,求(2x^2+xy-y^2分之x^4-y^4)乘以(xy-y^2分之2x-y)÷(y分之x^2+y^2)^2的值
已知xyz≠0,x+3y+7z=0,3x-4y-18z=0,求(x^2+2y^2+8z^2)分之(3x^2+5y^2+6z^2)的值
已知x^2+4y^2-4x+4y+5=0,求(2x^2+xy-y^2分之x^4-y^4)乘以(xy-y^2分之2x-y)÷(y分之x^2+y^2)^2的值已知xyz≠0,x+3y+7z=0,3x-4y-18z=0,求(x^2+2y^2+8z^2)分之(3x^2+5y^2+6z^2)的值
x^2+4y^2-4x+4y+5=0,
(x-2)^2+(2y+1)^2=0,
x=2,y=-1/2,
(2x^2+xy-y^2分之x^4-y^4)*(xy-y^2分之2x-y)/[(x^2+y^2)/y]^2
=[(x-y)(x+y)(x^2+y^2)/(2x-y)(x+y)](2x-y)/([y(x-y)]*y^2/(x^2+y^2)^2
=y/(x^2+y^2)
=(-1/2)/(2^2+1/4)=-2/17.
x+3y+7z=0,3x-4y-18z=0,
x=2z,y=-3z,
(3x^2+5y^2+6z^2)/(x^2+2y^2+8z^2)
=(12z^2+45z^2+6z^2)/(4z^2+18z^2+8z^2)
=21/10.
x^2+4y^2-4x+4y+5=0
(x-2)^2+(2y+1)^2=0
(x-2)^2=0
x-2=0
x=2
(2y+1)^2=0
2y+1=0
y=-1/2
^是什么计算符号呀?