34/9*43/4-3 4/9*2 1/2 = ? (13-7 5/7)*7 = ? ? /? - дробь. с примерами.

 1)
3 4/9 * 4 3/4 - 3 4/9 * 2 1/2 = 3 4/9 * (4 3/4 - 2 1/2) = 31/9 * (19/4 - 5/2) = 31/9 * (19/4 - 10/4) = 31/9 * 9/4 = 31/4 = 7 3/4.
2)
(13 - 7 5/7) * 7 = 13 * 7 - 7 5/7 * 7 = 91 - 54/7 * 7 = 91 - 54 = 37