| ( | 100 | + | 200 | ( | 4 | − | x | ) | ) | ( | 4 | − | x | − | 2 | ) | = | 0 |
| 方程左边 = | 100 | ( | 4 | − | x | − | 2 | ) | + | 200 | ( | 4 | − | x | ) | ( | 4 | − | x | − | 2 | ) |
| = | 100 | × | 4 | − | 100 | x | − | 100 | × | 2 | + | 200 | ( | 4 | − | x | ) | ( | 4 | − | x | − | 2 | ) |
| = | 400 | − | 100 | x | − | 200 | + | 200 | ( | 4 | − | x | ) | ( | 4 | − | x | − | 2 | ) |
| = | 200 | − | 100 | x | + | 200 | ( | 4 | − | x | ) | ( | 4 | − | x | − | 2 | ) |
| = | 200 | − | 100 | x | + | 200 | × | 4 | ( | 4 | − | x | − | 2 | ) | − | 200 | x | ( | 4 | − | x | − | 2 | ) |
| = | 200 | − | 100 | x | + | 800 | ( | 4 | − | x | − | 2 | ) | − | 200 | x | ( | 4 | − | x | − | 2 | ) |
| = | 200 | − | 100 | x | + | 800 | × | 4 | − | 800 | x | − | 800 | × | 2 | − | 200 | x | ( | 4 | − | x | − | 2 | ) |
| = | 200 | − | 100 | x | + | 3200 | − | 800 | x | − | 1600 | − | 200 | x | ( | 4 | − | x | − | 2 | ) |
| = | 1800 | − | 900 | x | − | 200 | x | ( | 4 | − | x | − | 2 | ) |
| = | 1800 | − | 900 | x | − | 200 | x | × | 4 | + | 200 | x | x | + | 200 | x | × | 2 |
| = | 1800 | − | 900 | x | − | 800 | x | + | 200 | x | x | + | 400 | x |
| = | 1800 | − | 1300 | x | + | 200 | x | x |
| 1800 | − | 1300 | x | + | 200 | x | x | = | 0 |
| x2= | 9 2 |