已知x-y=5,y-z=3,求x^2+y^2+z^2-xy-yz-xz的值

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已知x-y=5,y-z=3,求x^2+y^2+z^2-xy-yz-xz的值已知x-y=5,y-z=3,求x^2+y^2+z^2-xy-yz-xz的值已知x-y=5,y-z=3,求x^2+y^2+z^2

已知x-y=5,y-z=3,求x^2+y^2+z^2-xy-yz-xz的值
已知x-y=5,y-z=3,求x^2+y^2+z^2-xy-yz-xz的值

已知x-y=5,y-z=3,求x^2+y^2+z^2-xy-yz-xz的值
x-y=5,y-z=3
两个式子相加得：
x-z=8
原式=[（x-y)2+(y-z)2+(x-z)2]/2=(25+9+64)/2=49

x-z=8,原式=[（x-y)2+(y-z)2+(x-z)2]/2=(25+9+64)/2=49

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