Ответ:

Пошаговое объяснение:

(1 1/4)*2 = 5/4*2/1 = 5/2 = 2 1/2

(11/35 * 5/9)*1 4/5 = 11/63 * 1 4/5 = 11/63 * 9/5 = 11/35

(13/78*3/5)*1 2/3 = 13/130 * 1 2/3 = 1/10 * 5/2 = 1/4