| ( | y | − | 2500 | ) | ( | 4 | ( | 2900 | − | y | ) | ÷ | 50 | + | 8 | ) | = | 5000 |
| 方程左边 = | y | ( | 4 | ( | 2900 | − | y | ) | ÷ | 50 | + | 8 | ) | − | 2500 | ( | 4 | ( | 2900 | − | y | ) | ÷ | 50 | + | 8 | ) |
| = | y | × | 4 | ( | 2900 | − | y | ) | ÷ | 50 | + | y | × | 8 | − | 2500 | ( | 4 | ( | 2900 | − | y | ) | ÷ | 50 | + | 8 | ) |
| = | y | × | 2 25 | ( | 2900 | − | y | ) | + | y | × | 8 | − | 2500 | ( | 4 | ( | 2900 | − | y | ) | ÷ | 50 | + | 8 | ) |
| = | y | × | 2 25 | × | 2900 | − | y | × | 2 25 | y | + | 8 | y | − | 2500 | ( | 4 | ( | 2900 | − | y | ) | ÷ | 50 | + | 8 | ) |
| = | y | × | 232 | − | y | × | 2 25 | y | + | 8 | y | − | 2500 | ( | 4 | ( | 2900 | − | y | ) | ÷ | 50 | + | 8 | ) |
| = | 240 | y | − | y | × | 2 25 | y | − | 2500 | ( | 4 | ( | 2900 | − | y | ) | ÷ | 50 | + | 8 | ) |
| = | 240 | y | − | y | × | 2 25 | y | − | 2500 | × | 4 | ( | 2900 | − | y | ) | ÷ | 50 | − | 2500 | × | 8 |
| = | 240 | y | − | y | × | 2 25 | y | − | 200 | ( | 2900 | − | y | ) | − | 20000 |
| = | 240 | y | − | y | × | 2 25 | y | − | 200 | × | 2900 | + | 200 | y | − | 20000 |
| = | 240 | y | − | y | × | 2 25 | y | − | 580000 | + | 200 | y | − | 20000 |
| = | 440 | y | − | y | × | 2 25 | y | − | 600000 |
| 440 | y | − | y | × | 2 25 | y | − | 600000 | = | 5000 |