| ( | 100 | + | ( | a | − | 1 | ) | × | 258 | ) | ÷ | 19 | = | ( | a | × | 258 | ) | ÷ | 25 |
| 方程左边 = | 100 | × | 1 19 | + | ( | a | − | 1 | ) | × | 258 | × | 1 19 |
| = | 100 19 | + | ( | a | − | 1 | ) | × | 258 19 |
| = | 100 19 | + | a | × | 258 19 | − | 1 | × | 258 19 |
| = | 100 19 | + | a | × | 258 19 | − | 258 19 |
| = | - | 158 19 | + | 258 19 | a |
| - | 158 19 | + | 258 19 | a | = | ( | a | × | 258 | ) | ÷ | 25 |
| 方程右边 = | a | × | 258 | × | 1 25 |
| = | a | × | 258 25 |
| - | 158 19 | + | 258 19 | a | = | 258 25 | a |
258 19 | a | − | 258 25 | a | = | 158 19 |
1548 475 | a | = | 158 19 |
| a | = | 158 19 | ÷ | 1548 475 |
| = | 158 19 | × | 475 1548 |
| = | 79 | × | 25 774 |
| a | = | 1975 774 |
| a | = | 2.55168 |