Пошаговое объяснение:

а)

-1 7/15 * 7 11/13 + (-1 7/15) * 2 4/13 =

-1 7/15 * (7 11/13 + 2 4/13) =

-1 7/15 * 9 15/13 = -1 7/15 * 10 2/13 =

-22/15 * 132/13 = -2904/195 =

-14 174/195 = -14 58/65

б)

12(-1 1/12 + 2 1/2 - 3 1/6) =

12(-1 1/12 + 2 6/12 - 3 2/12) =

12(1 5/12 - 3 2/12) = 12(1 5/12 - 2 14/12) =

12 * (-1 9/12) = 12 * (-21/12) = 1 * (-21/1) = -21/1 = -21