| x | − | 80 | x | ÷ | ( | 120 | + | x | ) | = | 6 25 | x | + | 144 5 |
| 方程两边同时乘以: | ( | 120 | + | x | ) |
| x | ( | 120 | + | x | ) | − | 80 | x | = | 6 25 | x | ( | 120 | + | x | ) | + | 144 5 | ( | 120 | + | x | ) |
| x | × | 120 | + | x | x | − | 80 | x | = | 6 25 | x | ( | 120 | + | x | ) | + | 144 5 | ( | 120 | + | x | ) |
| x | × | 120 | + | x | x | − | 80 | x | = | 6 25 | x | × | 120 | + | 6 25 | x | x | + | 144 5 | ( | 120 | + | x | ) |
| x | × | 120 | + | x | x | − | 80 | x | = | 144 5 | x | + | 6 25 | x | x | + | 144 5 | ( | 120 | + | x | ) |
| 40 | x | + | x | x | = | 144 5 | x | + | 6 25 | x | x | + | 144 5 | ( | 120 | + | x | ) |
| 40 | x | + | x | x | = | 144 5 | x | + | 6 25 | x | x | + | 144 5 | × | 120 | + | 144 5 | x |
| 40 | x | + | x | x | = | 144 5 | x | + | 6 25 | x | x | + | 3456 | + | 144 5 | x |
| 40 | x | + | x | x | = | 288 5 | x | + | 6 25 | x | x | + | 3456 |