решит уровнение 3/7х -5/6*1 2/13=2,5

3/7х - 5/6 * 1 2/13 = 2,5;

3/7х - 5/6 * (1 * 13 + 2)/13 = 2,5;

3/7х - 5/6 * (13 + 2)/13 = 2,5;

3/7х - 5/6 * 15/13 = 2,5;

3/7х - (5 * 15)/(6 * 13) = 2,5;

3/7х - (5 * 5 * 3)/(3 * 2 * 13) = 2,5;

3/7х - (5 * 5)/(2 * 13) = 2,5;

3/7х - 25/26 = 2,5;

3/7х = 2,5 + 25/26;

3/7х = 2 5/10 + 25/26;

3/7х = 2 + 5/(5 * 2) + 25/26;

3/7х = 2 + 1/2 + 25/26;

3/7х = 2 + (1 * 13)/(2 * 13) + 25/26;

3/7х = 2 + 13/26 + 25/26;

3/7х = 2 + (13 + 25)/26;

3/7х = 2 + 38/26;

3/7х = 2 + 1 12/26;

3/7х = 2 + 1 6/13;

3/7х = 3 6/13;

х = 3 6/13 : 3/7;

х = (3 * 13 + 6)/13 : 3/7;

х = 45/13 * 7/3;

х = (15 * 7)/13;

х = 105/13;

х = 8 1/13.