(найдите значение выражения ( 5 3/5-1 1/3):(7 7/12-2 1/4)* 1,25 Решите

1

1) 5 3/5 - 1 1/3 = 28/5 - 4/3 = (28 * 3 - 4 * 5)/15 = (84 - 20)/15 = 64/15 = 4 4/15;

2) 7 7/12 - 2 1/4 = 91/12 - 9/4 = (91 * 1 - 9 * 3)/12 = (91 - 27)/12 = 64/12 = 16/3 = 5 1/3;

3) 4 4/15 : 5 1/3 = 64/15 : 16/3 = 64/15 * 3/16 = 4/5;

4) 4/5 * 1,25 = 0,8 * 1,25 = 1.

Ответ: 1.

2

8/3х - 12/7 = 31/21;

8/3х = 31/21 + 12/7;

8/3х = (31 * 1 + 12 * 3)/21;

8/3х = (31 + 36)/21;

8/3х = 67/21;

х = 67/21 : 8/3;

х = 67/21 * 3/8;

х = 67/56;

х = 1 11/56.

Ответ: 1 11/56.