| ( | ( | X | − | 300 | ) | × | 3 4 | − | ( | 4000 | × | 3 25 | ) | ) | ÷ | 4 | = | ( | ( | X | − | 300 | ) | × | 3 4 | ) | ÷ | 5 |
| Left side of the equation = | ( | X | − | 300 | ) | × | 3 4 | × | 1 4 | − | ( | 4000 | × | 3 25 | ) | × | 1 4 |
| = | ( | X | − | 300 | ) | × | 3 16 | − | ( | 4000 | × | 3 25 | ) | × | 1 4 |
| = | X | × | 3 16 | − | 300 | × | 3 16 | − | ( | 4000 | × | 3 25 | ) | × | 1 4 |
| = | X | × | 3 16 | − | 225 4 | − | ( | 4000 | × | 3 25 | ) | × | 1 4 |
| = | 3 16 | X | − | 225 4 | − | 4000 | × | 3 25 | × | 1 4 |
| = | 3 16 | X | − | 225 4 | − | 120 |
| = | 3 16 | X | − | 705 4 |
3 16 | X | − | 705 4 | = | ( | ( | X | − | 300 | ) | × | 3 4 | ) | ÷ | 5 |
| Right side of the equation = | ( | X | − | 300 | ) | × | 3 4 | × | 1 5 |
| = | ( | X | − | 300 | ) | × | 3 20 |
| = | X | × | 3 20 | − | 300 | × | 3 20 |
| = | X | × | 3 20 | − | 45 |
3 16 | X | − | 705 4 | = | 3 20 | X | − | 45 |
3 16 | X | − | 3 20 | X | = | - | 45 | + | 705 4 |
3 80 | X | = | - | 45 | + | 705 4 |
3 80 | X | = | 525 4 |
| X | = | 525 4 | ÷ | 3 80 |
| = | 525 4 | × | 80 3 |
| = | 175 | × | 20 |
| X | = | 3500 |