admin百科知識 2022-02-13 0:28:22 已知x-y=4,y-z=2,求x^2+y^2+z^2-xy-yz-xz的值已知x-y=4,y-z=2,求x^2 y^2 z^2-xy-yz-xz的值網友廻答：匿名網友x-y=4y-z=2兩式相加：x-z=6x^2 y^2 z^2-xy-yz-xz=1/2*(x^2 y^2-2xy x^2 z^2-2xz y^2 z^2-2yz)=1/2*[(x-y)^2 (x-z)^2 (y-z)^2]=1/2*(4^2 6^2 2^2)=1/2*(16 36 4)=28 db標簽 生活常識_百科知識_各類知識大全»已知x-y=4,y-z=2,求x^2+y^2+z^2-xy-yz-xz的值
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