697 100 | = | ( | 5 2 | u | ) | ÷ | ( | u | − | 5 2 | ) |
| 方程两边同时乘以: | ( | u | − | 5 2 | ) |
697 100 | ( | u | − | 5 2 | ) | = | ( | 5 2 | u | ) |
697 100 | u | − | 697 100 | × | 5 2 | = | ( | 5 2 | u | ) |
697 100 | u | − | 697 100 | × | 5 2 | = | 5 2 | u |
697 100 | u | − | 697 40 | = | 5 2 | u |
697 100 | u | − | 5 2 | u | = | 697 40 |
447 100 | u | = | 697 40 |
| u | = | 697 40 | ÷ | 447 100 |
| = | 697 40 | × | 100 447 |
| = | 697 2 | × | 5 447 |
| u | = | 3485 894 |
| u | = | 3.89821 |