| ( | 1 100 | + | a | ) | ÷ | ( | 1 10 | − | a | ) | × | ( | 1 10 | − | a | ) | = | 149 50 |
| 方程两边同时乘以: | ( | 1 10 | − | a | ) |
| ( | 1 100 | + | a | ) | ( | 1 10 | − | a | ) | = | 149 50 | ( | 1 10 | − | a | ) |
1 100 | ( | 1 10 | − | a | ) | + | a | ( | 1 10 | − | a | ) | = | 149 50 | ( | 1 10 | − | a | ) |
1 100 | ( | 1 10 | − | a | ) | + | a | ( | 1 10 | − | a | ) | = | 149 50 | × | 1 10 | − | 149 50 | a |
1 100 | ( | 1 10 | − | a | ) | + | a | ( | 1 10 | − | a | ) | = | 149 500 | − | 149 50 | a |
1 100 | × | 1 10 | − | 1 100 | a | + | a | ( | 1 10 | − | a | ) | = | 149 500 | − | 149 50 | a |
1 1000 | − | 1 100 | a | + | a | ( | 1 10 | − | a | ) | = | 149 500 | − | 149 50 | a |
1 1000 | − | 1 100 | a | + | a | × | 1 10 | − | a | a | = | 149 500 | − | 149 50 | a |
1 1000 | + | 9 100 | a | − | a | a | = | 149 500 | − | 149 50 | a |
| a= | 297 100 |