| ( | 90 | − | 80 | ) | ÷ | ( | 633 20 | − | 713 20 | ) | = | ( | 4057 50 | − | 80 | ) | ÷ | ( | x | − | 713 20 | ) |
| 方程两边同时乘以: | ( | 633 20 | − | 713 20 | ) | , | ( | x | − | 713 20 | ) |
| ( | 90 | − | 80 | ) | ( | x | − | 713 20 | ) | = | ( | 4057 50 | − | 80 | ) | ( | 633 20 | − | 713 20 | ) |
| 90 | ( | x | − | 713 20 | ) | − | 80 | ( | x | − | 713 20 | ) | = | ( | 4057 50 | − | 80 | ) | ( | 633 20 | − | 713 20 | ) |
| 90 | ( | x | − | 713 20 | ) | − | 80 | ( | x | − | 713 20 | ) | = | 4057 50 | ( | 633 20 | − | 713 20 | ) | − | 80 | ( | 633 20 | − | 713 20 | ) |
| 90 | x | − | 90 | × | 713 20 | − | 80 | ( | x | − | 713 20 | ) | = | 4057 50 | ( | 633 20 | − | 713 20 | ) | − | 80 | ( | 633 20 | − | 713 20 | ) |
| 90 | x | − | 90 | × | 713 20 | − | 80 | ( | x | − | 713 20 | ) | = | 4057 50 | × | 633 20 | − | 4057 50 | × | 713 20 | − | 80 | ( | 633 20 | − | 713 20 | ) |
| 90 | x | − | 6417 2 | − | 80 | ( | x | − | 713 20 | ) | = | 2568081 1000 | − | 2892641 1000 | − | 80 | ( | 633 20 | − | 713 20 | ) |
| 90 | x | − | 6417 2 | − | 80 | ( | x | − | 713 20 | ) | = | - | 8114 25 | − | 80 | ( | 633 20 | − | 713 20 | ) |
| 90 | x | − | 6417 2 | − | 80 | x | + | 80 | × | 713 20 | = | - | 8114 25 | − | 80 | ( | 633 20 | − | 713 20 | ) |
| 90 | x | − | 6417 2 | − | 80 | x | + | 80 | × | 713 20 | = | - | 8114 25 | − | 80 | × | 633 20 | + | 80 | × | 713 20 |
| 90 | x | − | 6417 2 | − | 80 | x | + | 2852 | = | - | 8114 25 | − | 2532 | + | 2852 |
| 10 | x | − | 713 2 | = | - | 114 25 |
| 10 | x | = | - | 114 25 | + | 713 2 |
| 10 | x | = | 17597 50 |
| x | = | 17597 50 | ÷ | 10 |
| = | 17597 50 | × | 1 10 |
| x | = | 17597 500 |
| x | = | 35.194 |