| 140 | x | + | ( | 1 | + | x | ) | × | 5 | x | − | ( | 800 | + | 80 | x | ) | × | 24 5 | = | 0 |
| 方程左边 = | 140 | x | + | 1 | × | 5 | x | + | x | × | 5 | x | − | ( | 800 | + | 80 | x | ) | × | 24 5 |
| = | 140 | x | + | 5 | x | + | x | × | 5 | x | − | ( | 800 | + | 80 | x | ) | × | 24 5 |
| = | 145 | x | + | x | × | 5 | x | − | ( | 800 | + | 80 | x | ) | × | 24 5 |
| = | 145 | x | + | x | × | 5 | x | − | 800 | × | 24 5 | − | 80 | x | × | 24 5 |
| = | 145 | x | + | x | × | 5 | x | − | 3840 | − | 384 | x |
| = | - | 239 | x | + | x | × | 5 | x | − | 3840 |
| - | 239 | x | + | x | × | 5 | x | − | 3840 | = | 0 |