| 120 | ( | 1 | − | x | ) | × | 800 | ( | 1 | + | 1 | ÷ | 3 | × | x | ) | = | 100 | ( | 1 | − | 1 | ÷ | 2 | × | x | ) | × | 1440 | − | 48000 |
| 方程左边 = | 96000 | ( | 1 | − | x | ) | ( | 1 | + | 1 | ÷ | 3 | × | x | ) |
| 96000 | ( | 1 | − | x | ) | ( | 1 | + | 1 | ÷ | 3 | × | x | ) | = | 100 | ( | 1 | − | 1 | ÷ | 2 | × | x | ) | × | 1440 | − | 48000 |
| 方程左边 = | 96000 | × | 1 | ( | 1 | + | 1 | ÷ | 3 | × | x | ) | − | 96000 | x | ( | 1 | + | 1 | ÷ | 3 | × | x | ) |
| = | 96000 | ( | 1 | + | 1 | ÷ | 3 | × | x | ) | − | 96000 | x | ( | 1 | + | 1 | ÷ | 3 | × | x | ) |
| = | 96000 | × | 1 | + | 96000 | × | 1 | ÷ | 3 | × | x | − | 96000 | x | ( | 1 | + | 1 | ÷ | 3 | × | x | ) |
| = | 96000 | + | 32000 | x | − | 96000 | x | ( | 1 | + | 1 | ÷ | 3 | × | x | ) |
| = | 96000 | + | 32000 | x | − | 96000 | x | × | 1 | − | 96000 | x | × | 1 | ÷ | 3 | × | x |
| = | 96000 | + | 32000 | x | − | 96000 | x | − | 32000 | x | x |
| = | 96000 | − | 64000 | x | − | 32000 | x | x |
| 96000 | − | 64000 | x | − | 32000 | x | x | = | 100 | ( | 1 | − | 1 | ÷ | 2 | × | x | ) | × | 1440 | − | 48000 |
| 方程右边 = | 144000 | ( | 1 | − | 1 | ÷ | 2 | × | x | ) | − | 48000 |
| 96000 | − | 64000 | x | − | 32000 | x | x | = | 144000 | ( | 1 | − | 1 | ÷ | 2 | × | x | ) | − | 48000 |
| 方程右边 = | 144000 | × | 1 | − | 144000 | × | 1 | ÷ | 2 | × | x | − | 48000 |
| = | 144000 | − | 72000 | x | − | 48000 |
| = | 96000 | − | 72000 | x |
| 96000 | − | 64000 | x | − | 32000 | x | x | = | 96000 | − | 72000 | x |
| x2= | 1 4 |