4 3/4 - (x-2 5/8) = 3 5/6 9 9/28 - (4 5/21-x) = 6 2/7

а) 4 3/4 - (x - 2 5/8) = 3 5/6;

4 3/4 - х + 2 5/8 = 3 5/6;

4 3/4 + 2 5/8 - 3 5/6 = х;

19/4 + 21/8 - 23/6 = х;

114/24 + 63/24 - 92/24 = х;

(114 + 63 - 92) / 24 = х;

85/24 = х;

3 13/24 = х;

Проверка.

4 3/4 - х + 2 5/8 = 3 5/6;

19/4 - 85/24 + 21/8 = 3 5/6;

114/24 - 85/24 + 63/24 = 3 5/6;

92/24 = 3 5/6;

3 20/24 = 3 5/6;

3 5/6 = 3 5/6;

Уравнение решено правильно.

б) 9 9/28 - (4 5/21 - x) = 6 2/7;

261/28 - 89/21 + х = 44/7;

х = 44/7 - 261/28 + 89/21;

х = 528/84 - 783/84 + 356/84;

х = 101/84 = 1 17/84;

Проверка.

261/28 - 89/21 + 101/84 = 6 2/7;

783/84 - 356/84 + 101/84 = 6 2/7;

528/84 = 6 2/7;

6 24/84 = 6 2/7;

6 2/7 = 6 2/7;

Уравнение решено правильно.