| ( | 63000 | × | 12 | − | 4500 | × | 12 | − | 3000 | × | 12 | − | 70 100 | × | 15 | X | ( | 49 1000 | + | 2 100 | ) | ÷ | ( | 30 100 | × | 15 | X | + | 5 100 | × | 15 | X | ) | ) | = | 19 500 |
| 63000 | × | 12 | − | 4500 | × | 12 | − | 3000 | × | 12 | − | 70 100 | × | 15 | X | ( | 49 1000 | + | 2 100 | ) | ÷ | ( | 30 100 | × | 15 | X | + | 5 100 | × | 15 | X | ) | = | 19 500 |
| 756000 | − | 54000 | − | 36000 | − | 21 2 | X | ( | 49 1000 | + | 2 100 | ) | ÷ | ( | 30 100 | × | 15 | X | + | 5 100 | × | 15 | X | ) | = | 19 500 |
| 666000 | − | 21 2 | X | ( | 49 1000 | + | 2 100 | ) | ÷ | ( | 30 100 | × | 15 | X | + | 5 100 | × | 15 | X | ) | = | 19 500 |
| Multiply both sides of the equation by: | ( | 30 100 | × | 15 | X | + | 5 100 | × | 15 | X | ) |
| 666000 | ( | 30 100 | × | 15 | X | + | 5 100 | × | 15 | X | ) | − | 21 2 | X | ( | 49 1000 | + | 2 100 | ) | = | 19 500 | ( | 30 100 | × | 15 | X | + | 5 100 | × | 15 | X | ) |
| 666000 | × | 30 100 | × | 15 | X | + | 666000 | × | 5 100 | × | 15 | X | − | 21 2 | X | ( | 49 1000 | + | 2 100 | ) | = | 19 500 | ( | 30 100 | × | 15 | X | + | 5 100 | × | 15 | X | ) |
| 666000 | × | 30 100 | × | 15 | X | + | 666000 | × | 5 100 | × | 15 | X | − | 21 2 | X | ( | 49 1000 | + | 2 100 | ) | = | 19 500 | × | 30 100 | × | 15 | X | + | 19 500 | × | 5 100 | × | 15 | X |
| 2997000 | X | + | 499500 | X | − | 21 2 | X | ( | 49 1000 | + | 2 100 | ) | = | 171 1000 | X | + | 57 2000 | X |
| 3496500 | X | − | 21 2 | X | ( | 49 1000 | + | 2 100 | ) | = | 399 2000 | X |
| 3496500 | X | − | 21 2 | X | × | 49 1000 | − | 21 2 | X | × | 2 100 | = | 399 2000 | X |
| 3496500 | X | − | 1029 2000 | X | − | 21 100 | X | = | 399 2000 | X |