| 2400 | ( | 1 | − | 1 | ÷ | 3 | × | a | ) | × | 100 | ( | 1 | + | 5 | ÷ | 2 | × | a | ) | − | 1600 | × | 100 | ( | 1 | + | 5 | ÷ | 2 | × | a | ) | = | 80000 |
| 方程左边 = | 240000 | ( | 1 | − | 1 | ÷ | 3 | × | a | ) | ( | 1 | + | 5 | ÷ | 2 | × | a | ) | − | 160000 | ( | 1 | + | 5 | ÷ | 2 | × | a | ) |
| 240000 | ( | 1 | − | 1 | ÷ | 3 | × | a | ) | ( | 1 | + | 5 | ÷ | 2 | × | a | ) | − | 160000 | ( | 1 | + | 5 | ÷ | 2 | × | a | ) | = | 80000 |
| 方程左边 = | 240000 | × | 1 | ( | 1 | + | 5 | ÷ | 2 | × | a | ) | − | 240000 | × | 1 | ÷ | 3 | × | a | ( | 1 | + | 5 | ÷ | 2 | × | a | ) | − | 160000 | ( | 1 | + | 5 | ÷ | 2 | × | a | ) |
| = | 240000 | ( | 1 | + | 5 | ÷ | 2 | × | a | ) | − | 80000 | a | ( | 1 | + | 5 | ÷ | 2 | × | a | ) | − | 160000 | ( | 1 | + | 5 | ÷ | 2 | × | a | ) |
| = | 240000 | × | 1 | + | 240000 | × | 5 | ÷ | 2 | × | a | − | 80000 | a | ( | 1 | + | 5 | ÷ | 2 | × | a | ) | − | 160000 | ( | 1 | + | 5 | ÷ | 2 | × | a | ) |
| = | 240000 | + | 600000 | a | − | 80000 | a | ( | 1 | + | 5 | ÷ | 2 | × | a | ) | − | 160000 | ( | 1 | + | 5 | ÷ | 2 | × | a | ) |
| = | 240000 | + | 600000 | a | − | 80000 | a | × | 1 | − | 80000 | a | × | 5 | ÷ | 2 | × | a | − | 160000 |
| = | 240000 | + | 600000 | a | − | 80000 | a | − | 200000 | a | a | − | 160000 | ( | 1 | + | 5 | ÷ | 2 | × | a | ) |
| = | 240000 | + | 520000 | a | − | 200000 | a | a | − | 160000 | ( | 1 | + | 5 | ÷ | 2 | × | a | ) |
| = | 240000 | + | 520000 | a | − | 200000 | a | a | − | 160000 | × | 1 | − | 160000 | × | 5 | ÷ | 2 | × | a |
| = | 240000 | + | 520000 | a | − | 200000 | a | a | − | 160000 | − | 400000 | a |
| = | 80000 | + | 120000 | a | − | 200000 | a | a |
| 80000 | + | 120000 | a | − | 200000 | a | a | = | 80000 |
| a2= | 3 5 |