639 2000 | = | ( | 321 100 | ( | 1 | + | x | ) | ) | ÷ | 31 10 | + | x |
| Right side of the equation = | 321 100 | ( | 1 | + | x | ) | × | 10 31 | + | x |
| = | 321 310 | ( | 1 | + | x | ) | + | x |
| = | 321 310 | × | 1 | + | 321 310 | x | + | x |
| = | 321 310 | + | 321 310 | x | + | x |
| = | 321 310 | + | 631 310 | x |
639 2000 | = | 321 310 | + | 631 310 | x |
| - | 631 310 | x | = | 321 310 | − | 639 2000 |
| - | 631 310 | x | = | 44391 62000 |
| - | 44391 62000 | = | 631 310 | x |
631 310 | x | = | - | 44391 62000 |
| x | = | - | 44391 62000 | ÷ | 631 310 |
| = | - | 44391 62000 | × | 310 631 |
| = | - | 44391 200 | × | 1 631 |
| x | = | - | 44391 126200 |
| x | = | - 0.351751 |