| A | ( | 45 100 | − | 15 200 | ) | − | ( | 4000 | + | A | ) | × | 5 100 | ( | 1 | − | 50 100 | ) | − | ( | 2000 | − | 500 | ) | = | 0 |
| 方程左边 = | A | × | 45 100 | − | A | × | 15 200 | − | ( | 4000 | + | A | ) | × | 5 100 | ( | 1 | − | 50 100 | ) | − | ( | 2000 | − | 500 | ) |
| = | 3 8 | A | − | ( | 4000 | + | A | ) | × | 5 100 | ( | 1 | − | 50 100 | ) | − | ( | 2000 | − | 500 | ) |
| = | 3 8 | A | − | 4000 | × | 5 100 | ( | 1 | − | 50 100 | ) | − | A | × | 5 100 | ( | 1 | − | 50 100 | ) | − | ( | 2000 | − | 500 | ) |
| = | 3 8 | A | − | 200 | ( | 1 | − | 50 100 | ) | − | A | × | 5 100 | ( | 1 | − | 50 100 | ) | − | ( | 2000 | − | 500 | ) |
| = | 3 8 | A | − | 200 | × | 1 | + | 200 | × | 50 100 | − | A | × | 5 100 | ( | 1 | − | 50 100 | ) | − | ( | 2000 | − | 500 | ) |
| = | 3 8 | A | − | 200 | + | 100 | − | A | × | 5 100 | ( | 1 | − | 50 100 | ) | − | ( | 2000 | − | 500 | ) |
| = | 3 8 | A | − | 100 | − | A | × | 5 100 | ( | 1 | − | 50 100 | ) | − | ( | 2000 | − | 500 | ) |
| = | 3 8 | A | − | 100 | − | A | × | 5 100 | × | 1 | + | A | × | 5 100 | × | 50 100 | − | ( | 2000 | − | 500 | ) |
| = | 3 8 | A | − | 100 | − | A | × | 1 20 | + | A | × | 1 40 | − | ( | 2000 | − | 500 | ) |
| = | 7 20 | A | − | 100 | − | ( | 2000 | − | 500 | ) |
| = | 7 20 | A | − | 100 | − | 2000 | + | 500 |
| = | 7 20 | A | − | 1600 |
7 20 | A | − | 1600 | = | 0 |
7 20 | A | = | 0 | + | 1600 |
7 20 | A | = | 1600 |
| A | = | 1600 | ÷ | 7 20 |
| = | 1600 | × | 20 7 |
| A | = | 32000 7 |
| A | = | 4571.428571 |