giải hệ pt: \(x_1+x_2+x_3+...\) \(+x_{2000}=1\)
\(x_1\) \(+x_3+x_4+....\) \(+x_{2000}=2\)
\(x_1+x_2\) \(+x_4+....\) \(+x_{2000}=3\)
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\(x_1+x_2+x_3+x_4+......+x_{2000}=2000\)