Решите уравнение: (3/4*x-2/5)*20=22

(3/4 * х - 2/5) * 20 = 22;

3/4 * х * 20 - 2/5 * 20 = 22;

(3 * 20)/4 * х - (2 * 20)/5 = 22;

(3 * 4 * 5)/4 * х - (2 * 4 * 5)/5 = 22;

3 * 5 * х - 2 * 4 = 22;

15х - 8 = 22;

15х = 22 + 8;

15х = 30;

х = 30 : 15;

х = 2.

Ответ: х = 2.

Решим сходственное уравнение:

(2/5х - 7/10) * 30 = 18;

2/5х * 30 - 7/10 * 30 = 18;

(2 * 30)/5х - (7 * 30)/10 = 18;

(2 * 5 * 6)/5х - (7 * 3 * 10)/10 = 18;

2 * 6х - 7 * 3 = 18;

12х - 21 = 18;

12х = 18 + 21;

12х = 39;

х = 39 : 12;

х = 3 (39 - 3 * 12)/12;

х = 3 (39 - 36)/12;

х = 3 3/12;

х = 3 3/(3 * 4);

х = 3 1/4.