| ( | 17 20 | X | − | 69 | ) | ÷ | ( | 17 20 | X | ) | = | 3 10 |
| 方程两边同时乘以: | ( | 17 20 | X | ) |
| ( | 17 20 | X | − | 69 | ) | = | 3 10 | ( | 17 20 | X | ) |
17 20 | X | − | 69 | = | 3 10 | ( | 17 20 | X | ) |
17 20 | X | − | 69 | = | 3 10 | × | 17 20 | X |
17 20 | X | − | 69 | = | 51 200 | X |
17 20 | X | − | 51 200 | X | = | 69 |
119 200 | X | = | 69 |
| X | = | 69 | ÷ | 119 200 |
| = | 69 | × | 200 119 |
| X | = | 13800 119 |
| X | = | 115.966387 |