| 300 | ( | 1 | + | a | ) | + | 200 | ( | 1 | + | 3 | a | ) | ( | 1 | − | a | ) | = | 500 | ( | 1 | + | 29 25 | a | ) |
| 方程左边 = | 300 | × | 1 | + | 300 | a | + | 200 | ( | 1 | + | 3 | a | ) | ( | 1 | − | a | ) |
| = | 300 | + | 300 | a | + | 200 | ( | 1 | + | 3 | a | ) | ( | 1 | − | a | ) |
| = | 300 | + | 300 | a | + | 200 | × | 1 | ( | 1 | − | a | ) | + | 200 | × | 3 | a | ( | 1 | − | a | ) |
| = | 300 | + | 300 | a | + | 200 | ( | 1 | − | a | ) | + | 600 | a | ( | 1 | − | a | ) |
| = | 300 | + | 300 | a | + | 200 | × | 1 | − | 200 | a | + | 600 | a | ( | 1 | − | a | ) |
| = | 300 | + | 300 | a | + | 200 | − | 200 | a | + | 600 | a | ( | 1 | − | a | ) |
| = | 500 | + | 100 | a | + | 600 | a | ( | 1 | − | a | ) |
| = | 500 | + | 100 | a | + | 600 | a | × | 1 | − | 600 | a | a |
| = | 500 | + | 100 | a | + | 600 | a | − | 600 | a | a |
| = | 500 | + | 700 | a | − | 600 | a | a |
| 500 | + | 700 | a | − | 600 | a | a | = | 500 | ( | 1 | + | 29 25 | a | ) |
| 方程右边 = | 500 | × | 1 | + | 500 | × | 29 25 | a |
| = | 500 | + | 580 | a |
| 500 | + | 700 | a | − | 600 | a | a | = | 500 | + | 580 | a |
| a2= | 1 5 |