已知x-y=-1,z-y=2,求x²+y²+z²-xy-yz-xz的值
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![已知x-y=-1,z-y=2,求x²+y²+z²-xy-yz-xz的值](/uploads/image/z/1660816-64-6.jpg?t=%E5%B7%B2%E7%9F%A5x-y%3D-1%2Cz-y%3D2%2C%E6%B1%82x%26%23178%3B%2By%26%23178%3B%2Bz%26%23178%3B-xy-yz-xz%E7%9A%84%E5%80%BC)
已知x-y=-1,z-y=2,求x²+y²+z²-xy-yz-xz的值
已知x-y=-1,z-y=2,求x²+y²+z²-xy-yz-xz的值
已知x-y=-1,z-y=2,求x²+y²+z²-xy-yz-xz的值
(x²+y²+z²-xy-yz-xz)*2=(x-y)^2+(x-z)^2+(z-y)^2=
(-1)^2+(3)^2+(2)^2=14
14/2=7
(x-y=-1,z-y=2,所以z-x=3)