| ( | X | − | 180 | ) | ÷ | ( | 1000 | + | 500 | ) | = | ( | X | − | 180 | − | 4000 | × | 8 100 | ) | ÷ | 1000 |
| Multiply both sides of the equation by: | ( | 1000 | + | 500 | ) |
| ( | X | − | 180 | ) | = | ( | X | − | 180 | − | 4000 | × | 8 100 | ) | ÷ | 1000 | × | ( | 1000 | + | 500 | ) |
| X | − | 180 | = | ( | X | − | 180 | − | 4000 | × | 8 100 | ) | ÷ | 1000 | × | ( | 1000 | + | 500 | ) |
| X | − | 180 | = | X | ÷ | 1000 | × | ( | 1000 | + | 500 | ) | − | 180 | ÷ | 1000 | × | ( | 1000 | + | 500 | ) | − | 4000 | × | 8 100 | ÷ | 1000 | × | ( | 1000 | + | 500 | ) |
| X | − | 180 | = | X | × | 1 1000 | ( | 1000 | + | 500 | ) | − | 9 50 | ( | 1000 | + | 500 | ) | − | 8 25 | ( | 1000 | + | 500 | ) |
| X | − | 180 | = | X | × | 1 1000 | × | 1000 | + | X | × | 1 1000 | × | 500 | − | 9 50 | ( | 1000 | + | 500 | ) | − | 8 25 | ( | 1000 | + | 500 | ) |
| X | − | 180 | = | X | × | 1 | + | X | × | 1 2 | − | 9 50 | ( | 1000 | + | 500 | ) | − | 8 25 | ( | 1000 | + | 500 | ) |
| X | − | 180 | = | 3 2 | X | − | 9 50 | ( | 1000 | + | 500 | ) | − | 8 25 | ( | 1000 | + | 500 | ) |
| X | − | 180 | = | 3 2 | X | − | 9 50 | × | 1000 | − | 9 50 | × | 500 | − | 8 25 | ( | 1000 | + | 500 | ) |
| X | − | 180 | = | 3 2 | X | − | 180 | − | 90 | − | 8 25 | ( | 1000 | + | 500 | ) |
| X | − | 180 | = | 3 2 | X | − | 270 | − | 8 25 | ( | 1000 | + | 500 | ) |
| X | − | 180 | = | 3 2 | X | − | 270 | − | 8 25 | × | 1000 | − | 8 25 | × | 500 |
| X | − | 180 | = | 3 2 | X | − | 270 | − | 320 | − | 160 |
| X | − | 180 | = | 3 2 | X | − | 750 |
| X | − | 3 2 | X | = | - | 750 | + | 180 |
| - | 1 2 | X | = | - | 750 | + | 180 |
| - | 1 2 | X | = | - | 570 |
| 570 | = | 1 2 | X |
1 2 | X | = | 570 |
| X | = | 570 | ÷ | 1 2 |
| = | 570 | × | 2 |
| X | = | 1140 |