10) (7/18 + 11/12) : (- 19/48);

10) (7/18 + 11/12) : (- 19/48) = ((7 * 2)/(18 * 2) + (11 * 3)/(12 * 3)) : (-19/48) = (14/36 + 33/36) : (-19/48) = (14 + 33)/36 : (-19/48) = 47/36 * (-48/19) = - (47 * 48)/(36 * 19) = - (47 * 4)/(3 * 19) = -188/57 = -3 17/57

Ответ: -3 17/57