LinearSolve[{{6.314, -2.873, 2.479, 7.738}, {3.862, 5.829, -7.983, 0.560}, {-7.433, 4.607, 2.433, 4.869}, {6.320, 4.155, 3.149, -6.425}}, {9.857, 7.975, 7.462, 4.278}]

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