14 - 13,2:(3 11/21 - 2 6/15) =14 - 13,2:(1 11/21 - 6/15) = 14 - 13,2:(32/21 - 6/15) =
= 14 - 13,2:(160/105 - 42/105) =14 - 13,2:118/105 =14 - 132/10:118/105 =
= 14 - 132/10 * 105/118=14 - 132 *105/10 *118=14 - 66 *105/5 *118=
= 14 - 33 *105/5 *59 =14 - 33 *21/ 59 =14 - 693/ 59 =14 - 11 44/ 59 = 2 15/59