Решите неравенство: 1) 7< 2-5x< 13 2) 9< 3-4x< 15 3) x

1) 7<2-5x<13      2) 9<3-4x<15        3) x<или=3 - 1/x-1

  7-2+5х<13             9-3+4x<15          x=3-1/x-1

  5+5x<13                 6+4x<15              x=3x-1-x

  5x<13-5                  4x<15-6               x=2x-1

  5x<8                        4x<9                    x-2x=-1

  x<8-5                       x<9-4                  -x=-1

  x<3                          x<5                       x=1