| 15 | + | ( | x | × | 27 25 | + | 5 2 | ) | + | 3 20 | x | + | ( | 15 | × | 331 2000 | ) | = | 128 |
| 方程左边 = | 15 | + | x | × | 27 25 | + | 5 2 | + | 3 20 | x | + | ( | 15 | × | 331 2000 | ) |
| = | 35 2 | + | 123 100 | x | + | ( | 15 | × | 331 2000 | ) |
| = | 35 2 | + | 123 100 | x | + | 15 | × | 331 2000 |
| = | 35 2 | + | 123 100 | x | + | 993 400 |
| = | 7993 400 | + | 123 100 | x |
7993 400 | + | 123 100 | x | = | 128 |
123 100 | x | = | 128 | − | 7993 400 |
123 100 | x | = | 43207 400 |
| x | = | 43207 400 | ÷ | 123 100 |
| = | 43207 400 | × | 100 123 |
| = | 43207 4 | × | 1 123 |
| x | = | 43207 492 |
| x | = | 87.819106 |