Page 39 - Fixtures
P. 39

@ @pbjïØ Üa@                                    @RT

   .                            [Aust.MC 1981] ( )

87 4                                    0, 1, 2, …, 9

.                               .
  .
                                     ABC

              . 3 .8 7 4
                                       . 3 × 3 × 3 = 27

            28 [Aust.MC 1981] ( )

. n −1                    .n
. n(n − 1)
              .n(n − 1) = 56    . n(n − 1) = 28
     2
            n2 − n − 56 = 0           2
  .n = 8
            (n + 7)(n − 8) = 0

            n .n = −7 n = 8
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