| ( | 3 | − | a | ) | ( | 200 | + | 400 | a | ) | − | ( | 400 | a | + | 200 | ) | × | 2 | − | 24 | = | 200 |
| 方程左边 = | 3 | ( | 200 | + | 400 | a | ) | − | a | ( | 200 | + | 400 | a | ) | − | ( | 400 | a | + | 200 | ) | × | 2 | − | 24 |
| = | 3 | × | 200 | + | 3 | × | 400 | a | − | a | ( | 200 | + | 400 | a | ) | − | ( | 400 | a | + | 200 | ) | × | 2 | − | 24 |
| = | 600 | + | 1200 | a | − | a | ( | 200 | + | 400 | a | ) | − | ( | 400 | a | + | 200 | ) | × | 2 | − | 24 |
| = | 576 | + | 1200 | a | − | a | ( | 200 | + | 400 | a | ) | − | ( | 400 | a | + | 200 | ) | × | 2 |
| = | 576 | + | 1200 | a | − | a | × | 200 | − | a | × | 400 | a | − | ( | 400 | a | + | 200 | ) | × | 2 |
| = | 576 | + | 1000 | a | − | a | × | 400 | a | − | ( | 400 | a | + | 200 | ) | × | 2 |
| = | 576 | + | 1000 | a | − | a | × | 400 | a | − | 400 | a | × | 2 | − | 200 | × | 2 |
| = | 576 | + | 1000 | a | − | a | × | 400 | a | − | 800 | a | − | 400 |
| = | 176 | + | 200 | a | − | a | × | 400 | a |
| 176 | + | 200 | a | − | a | × | 400 | a | = | 200 |
| a1= | 1 5 |
| a2= | 3 10 |