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2013-04-23T16:27:36+02:00

B=12x(8/8-1/4)

   = 72

       8

   = 9

 

C= 13/15 - 4/15 x3/4

   = 40

     60

   = 0.666.....

2013-04-23T16:56:27+02:00

B= 12x(8/8-1/4)                                    C= 13/15-4/15x3/4

  = 12x(8/8-1x2/4x2)                                = 13/15 - 4x3/15x4

  = 12x(8/8-2/8)                                       = 13/15 - 12/60

  = 12x(6/8)                                             = 13x4/15x4 - 12/60

  = 12x6/8                                                = 52/60 - 12/60

  = 72/8                                                    = 52-12/60

  = 9                                                         = 40/60 = 0,6666666667