| ( | 1500000 | + | x | ) | × | 6 5 | + | ( | 1500000 | + | x | ) | = | 668588 |
| Left side of the equation = | 1500000 | × | 6 5 | + | x | × | 6 5 | + | ( | 1500000 | + | x | ) |
| = | 1800000 | + | x | × | 6 5 | + | ( | 1500000 | + | x | ) |
| = | 1800000 | + | 6 5 | x | + | 1500000 | + | x |
| = | 3300000 | + | 11 5 | x |
| 3300000 | + | 11 5 | x | = | 668588 |
11 5 | x | = | 668588 | − | 3300000 |
11 5 | x | = | - | 2631412 |
| x | = | - | 2631412 | ÷ | 11 5 |
| = | - | 2631412 | × | 5 11 |
| x | = | - | 13157060 11 |
| x | = | - 1196096.363636 |