(3целых 1/2 х Х -1/4) х8=3

(3 1/2 * х - 1/4) * 8 = 3.

Поделим уравнение на 8;

3 1/2 * х - 1/4 = 3/8;

3 1/2х = 3/8 + 1/4;

3 1/2х = 3/8 + (1 * 2)/(4 * 2);

3 1/2х = 3/8 + 2/8;

3 1/2х = (3 + 2)/8;

3 1/2х = 5/8;

х = 5/8 : 3 1/2;

х = 5/8 : (3 * 2 + 1)/2;

х = 5/8 : (6 + 1)/2;

х = 5/8 : 7/2;

х = 5/8 * 2/7;

х = (5 * 2)/(8 * 7);

х = (5 * 2)/(2 * 4 * 7);

х = 5/28.

Либо, поначалу раскроем скобки:

3 1/2х * 8 - 1/4 * 8 = 3;

(3 * 2 + 1)/2х * 8 - (4 * 2)/4 = 3;

7/2х * 8 - 2 = 3;

(7 * 2 * 4)/2х = 3 + 2;

7 * 4х = 5;

28х = 5;

х = 5/28.

Ответ: х = 5 28.