| ( | ( | A | − | 0 | ) | ( | 1 | − | 25 100 | ) | ) | ÷ | 150 | = | ( | ( | A | − | 0 | ) | ( | 1 | − | 25 100 | ) | − | 60 | ) | ÷ | 100 |
| 方程左边 = | ( | A | − | 0 | ) | ( | 1 | − | 25 100 | ) | × | 1 150 |
| = | A | ( | 1 | − | 25 100 | ) | × | 1 150 | − | 0 | ( | 1 | − | 25 100 | ) | × | 1 150 |
| = | A | ( | 1 | − | 25 100 | ) | × | 1 150 | − | 0 | ( | 1 | − | 25 100 | ) |
| = | A | × | 1 | × | 1 150 | − | A | × | 25 100 | × | 1 150 |
| = | A | × | 1 150 | − | A | × | 1 600 |
| = | 1 200 | A |
1 200 | A | = | ( | ( | A | − | 0 | ) | ( | 1 | − | 25 100 | ) | − | 60 | ) | ÷ | 100 |
| 方程右边 = | ( | A | − | 0 | ) | ( | 1 | − | 25 100 | ) | × | 1 100 | − | 60 | × | 1 100 |
| = | ( | A | − | 0 | ) | ( | 1 | − | 25 100 | ) | × | 1 100 | − | 3 5 |
| = | A | ( | 1 | − | 25 100 | ) | × | 1 100 | − | 0 | ( | 1 | − | 25 100 | ) | × | 1 100 | − | 3 5 |
| = | A | ( | 1 | − | 25 100 | ) | × | 1 100 | − | 0 | ( | 1 | − | 25 100 | ) | − | 3 5 |
| = | A | × | 1 | × | 1 100 | − | A | × | 25 100 | × | 1 100 | − | 0 | ( | 1 | − | 25 100 | ) | − | 3 5 |
| = | A | × | 1 100 | − | A | × | 1 400 | − | 0 | ( | 1 | − | 25 100 | ) | − | 3 5 |
| = | 3 400 | A | − | 0 | ( | 1 | − | 25 100 | ) | − | 3 5 |
| = | 3 400 | A | − | 0 | × | 1 | + | 0 | × | 25 100 | − | 3 5 |
| = | 3 400 | A | − | 0 | + | 0 | − | 3 5 |
| = | 3 400 | A | − | 3 5 |
1 200 | A | = | 3 400 | A | − | 3 5 |
1 200 | A | − | 3 400 | A | = | - | 3 5 |
| - | 1 400 | A | = | - | 3 5 |
3 5 | = | 1 400 | A |
1 400 | A | = | 3 5 |
| A | = | 3 5 | ÷ | 1 400 |
| = | 3 5 | × | 400 |
| = | 3 | × | 80 |
| A | = | 240 |