Линейная алгебра. Постникова Л.С - 19 стр.

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11   ⎧ x1 + 2 x2 − x3 − x4 = 5               12   ⎧ x1 + x2 − 3 x3 − 4 x4 = −5
     ⎪3 x + 5 x + 3 x = 18                        ⎪3 x − x + 3 x + x = 6
     ⎪ 1         2     4                          ⎪ 1 2            3     4
     ⎨                                            ⎨
     ⎪2 x1 − x2 + 2 x3 + x4 = −2                  ⎪ x1 + 8 x3 + 9 x4 = 18
     ⎪⎩4 x1 + x2 + x3 − 5 x4 = −2                 ⎪⎩− 2 x1 + 4 x2 − 7 x3 − x4 = −6
13   ⎧2 x1 + 3 x2 + x3 − x4 = 1              14   ⎧7 x1 − x2 + 8 x3 − x4 = −1
     ⎪ x − x + 5 x + 2 x = −4                     ⎪2 x + 2 x + x − 9 x = 12
     ⎪ 1 2           3      4                     ⎪ 1          2    3      4
     ⎨                                            ⎨
     ⎪3 x1 + x2 + x3 − 3 x4 = −3                  ⎪ x1 + x2 − 3 x3 + 5 x4 = 0
     ⎪⎩ x1 + x2 − x3 + 5 x4 = 7                   ⎪⎩ x1 − 2 x2 + 4 x3 + x4 = −6
15   ⎧3 x1 + x2 − x3 + 4 x4 = 6              16   ⎧ x1 − 3 x2 + x3 + x4 = −2
     ⎪ x − x + x − x = −3                         ⎪− 2 x + 5 x − 3 x − 2 x = 1
     ⎪ 1 2          3    4                        ⎪      1      2     3      4
     ⎨                                            ⎨
     ⎪2 x1 + 5 x2 + 3 x3 − x4 = 9                 ⎪ x1 − x2 + 4 x3 + x4 = 6
     ⎪⎩ x1 + 5 x3 + x4 = 1                        ⎪⎩5 x1 + 6 x2 − x3 − 4 x4 = 8
17   ⎧− 5 x1 + 4 x2 − x3 + 3 x4 = −8         18   ⎧ x1 − 10 x2 + 9 x3 − x4 = 0
     ⎪ x − 2 x + 5 x − x = 12                     ⎪5 x + 3 x + 2 x = 8
     ⎪ 1       2      3     4                     ⎪ 1         3      4
     ⎨                                            ⎨
     ⎪2 x1 + x2 + x3 − 2 x4 = 1                   ⎪ x1 − x2 + x3 + x4 = 1
     ⎪⎩6 x1 + 5 x2 − 4 x3 + 2 x4 = −5             ⎪⎩2 x1 + x2 − 3 x3 − x4 = 0
19   ⎧2 x1 + x2 + 5 x3 + x4 = −12            20   ⎧ x1 + 4 x2 − 4 x3 + x4 = −8
     ⎪3 x − 2 x + 4 x − 4 x = −18                 ⎪5 x + 11x − x − x = −6
     ⎪ 1         2       3     4                  ⎪ 1          2    3    4
     ⎨                                            ⎨
     ⎪− 2 x1 + 5 x2 − x3 + 5 x4 = 18              ⎪ x1 − x2 + 5 x3 + 2 x4 = 5
     ⎪⎩ x1 − 6 x2 − 7 x3 + x4 = 3                 ⎪⎩2 x1 − x2 − x3 − x4 = 3
21   ⎧ x1 + 2 x2 − x3 − x4 = −8              22   ⎧4 x1 + 5 x2 + 3 x3 − x4 = 7
     ⎪3 x + 5 x + 3 x = −14                       ⎪x + x + x + x = 0
     ⎪ 1         2     4                          ⎪ 1 2          3    4
     ⎨                                            ⎨
     ⎪2 x1 − x2 + x3 + 5 x4 = 11                  ⎪2 x1 − 3 x2 − 4 x3 + x4 = −5
     ⎪⎩ x1 − x2 − x3 + 2 x4 = 7                   ⎪⎩ x1 + 5 x2 − x3 − 2 x4 = −2
23   ⎧2 x1 + 3 x2 − 3 x3 + 2 x4 = −2         24   ⎧ x1 − 8 x2 + 9 x3 − x4 = 28
     ⎪5 x − x − x + 7 x = −9                      ⎪2 x + x + 10 x = −10
     ⎪ 1 2           3      4                     ⎪ 1 2              4
     ⎨                                            ⎨
     ⎪ x1 + 5 x2 + 4 x3 − x4 = 10                 ⎪2 x1 − 3 x2 − x3 − 2 x4 = −1
     ⎪⎩2 x1 − 2 x2 + 7 x3 + x4 = 4                ⎪⎩ x1 + 5 x2 + 6 x3 − 3 x4 = 21