3 10 | q | × | 2 | − | 4 | q | + | 15 | = | 1 10 | q | × | 2 | − | 2 | q | + | 15 |
| 方程左边 = | 3 5 | q | − | 4 | q | + | 15 |
| = | - | 17 5 | q | + | 15 |
| - | 17 5 | q | + | 15 | = | 1 10 | q | × | 2 | − | 2 | q | + | 15 |
| 方程右边 = | 1 5 | q | − | 2 | q | + | 15 |
| = | - | 9 5 | q | + | 15 |
| - | 17 5 | q | + | 15 | = | - | 9 5 | q | + | 15 |
| - | 17 5 | q | + | 9 5 | q | = | 15 | − | 15 |
| - | 8 5 | q | = | 15 | − | 15 |
| - | 8 5 | q | = | 0 |
| - | 0 | = | 8 5 | q |
8 5 | q | = | - | 0 |
| q | = | - | 0 | ÷ | 8 5 |
| = | - | 0 | × | 5 8 |
| q | = | 0 |