Решите уравнения: 1) 140-(х:7+29) 2)750:(5х-12)-56=34 3)100:(19+(15х-84):6)=4 4)(72-64:(40-8х)) 4=72

2) 750 : (5х - 12) - 56 = 34;

750 : (5х - 12) = 34 + 56;

750 : (5х - 12) = 90;

(5х - 12) = 750 : 90;

5х - 12 = 8 30/90 = 8 1/3;

5х = 8 1/3 + 12;

5х = 20 1/3;

х = 20 1/3 : 5 = 61 / (3 * 5) = 61 / 15 = 4 1/15;

Ответ: 4 1/15.

3) 100 : (19 + (15х - 84) : 6) = 4;

19 + (15х - 84) : 6 = 100 / 4;

19 + (15х - 84) : 6 = 25;

(15х - 84) : 6 = 25 - 19;

(15х - 84) : 6 = 6;

15х - 84 = 6 * 6;

15х - 84 = 36;

15х = 36 + 84;

15х = 120;

х = 120 / 15;

х = 8;

Ответ: 8.

4) (72 - 64 : (40 - 8х)) - 4 = 72;

72 - 64 : (40 - 8х) = 72 + 4;

72 - 64 : (40 - 8х) = 76;

64 : (40 - 8х) = 72 - 76;

64 : (40 - 8х) = -4;

40 - 8х = 64 / -4;

40 - 8х = -16;

8х = 40 - (-16) = 40 + 16 = 56;

х = 56 / 8;

х = 7;

Ответ: 7.