| 100 | − | ( | 20 | − | x | ) | ( | 10 | − | x | ) | ( | 1 2 | − | x | ) | = | x |
| 方程左边 = | 100 | − | 20 | ( | 10 | − | x | ) | ( | 1 2 | − | x | ) | + | x | ( | 10 | − | x | ) | ( | 1 2 | − | x | ) |
| = | 100 | − | 20 | × | 10 | ( | 1 2 | − | x | ) | + | 20 | x | ( | 1 2 | − | x | ) | + | x | ( | 10 | − | x | ) | ( | 1 2 | − | x | ) |
| = | 100 | − | 200 | ( | 1 2 | − | x | ) | + | 20 | x | ( | 1 2 | − | x | ) | + | x | ( | 10 | − | x | ) | ( | 1 2 | − | x | ) |
| = | 100 | − | 200 | × | 1 2 | + | 200 | x | + | 20 | x | ( | 1 2 | − | x | ) | + | x | ( | 10 | − | x | ) | ( | 1 2 | − | x | ) |
| = | 100 | − | 100 | + | 200 | x | + | 20 | x | ( | 1 2 | − | x | ) | + | x | ( | 10 | − | x | ) | ( | 1 2 | − | x | ) |
| = | 0 | + | 200 | x | + | 20 | x | ( | 1 2 | − | x | ) | + | x | ( | 10 | − | x | ) | ( | 1 2 | − | x | ) |
| = | 200 | x | + | 20 | x | × | 1 2 | − | 20 | x | x | + | x | ( | 10 | − | x | ) | ( | 1 2 | − | x | ) |
| = | 200 | x | + | 10 | x | − | 20 | x | x | + | x | ( | 10 | − | x | ) | ( | 1 2 | − | x | ) |
| = | 210 | x | − | 20 | x | x | + | x | ( | 10 | − | x | ) | ( | 1 2 | − | x | ) |
| = | 210 | x | − | 20 | x | x | + | x | × | 10 | ( | 1 2 | − | x | ) | − | x | x | ( | 1 2 | − | x | ) |
| = | 210 | x | − | 20 | x | x | + | x | × | 10 | × | 1 2 | − | x | × | 10 | x | − | x |
| = | 210 | x | − | 20 | x | x | + | x | × | 5 | − | x | × | 10 | x | − | x | x |
| = | 215 | x | − | 20 | x | x | − | x | × | 10 | x | − | x | x | ( | 1 2 | − | x | ) |
| = | 215 | x | − | 20 | x | x | − | x | × | 10 | x | − | x | x | × | 1 2 | + | x |
| 215 | x | − | 20 | x | x | − | x | × | 10 | x | − | x | x | × | 1 2 | + | x | = | x |