Найди число х для которого правильно равенство: а)х+1/8=3/5 б)1/3+х=5/12 в)х-3/20=1/5

а)

х = 3/5 - 1/8;

х = (3 * 8 - 1 * 5)/40;

х = (24 - 5)/40;

х = 19/40.

Проверка:

19/40 + 1/8 = 3/5;

(19 * 1 + 1 * 5)/40 = 3/5;

(19 + 5)/40 = 3/5;

24/40 = 3/5;

3/5 = 3/5.

Ответ: 19/40.

б) 1/3 + х = 5/12;

х = 5/12 - 1/3;

х = (5 * 1 - 1 * 4)/12;

х = (5 - 4)/12;

х = 1/12.

Проверка:

1/3 + 1/12 = 5/12;

(1 * 4 + 1 * 1)/12 = 5/12;

(4 + 1)/12 = 5/12;

5/12 = 5/12.

Ответ: 1/12.

в) х - 3/20 = 1/5;

х = 1/5 + 3/20;

х = (1 * 4 + 3 * 1)/20;

х = (4 + 3)/20;

х = 7/20.

Проверка:

7/20 - 3/20 = 1/5;

4/20 = 1/5;

1/5 = 1/5.

Ответ: 7/20.