| ( | 180 | − | 100 | ) | ÷ | ( | 200 | − | 100 | ) | × | ( | x | − | 5000 | ) | ÷ | ( | 7000 | − | 5000 | ) | = | 0 |
| 方程两边同时乘以: | ( | 200 | − | 100 | ) |
| ( | 180 | − | 100 | ) | ( | x | − | 5000 | ) | ÷ | ( | 7000 | − | 5000 | ) | = | 0 |
| 180 | ( | x | − | 5000 | ) | ÷ | ( | 7000 | − | 5000 | ) | − | 100 | ( | x | − | 5000 | ) | ÷ | ( | 7000 | − | 5000 | ) | = | 0 |
| 方程两边同时乘以: | ( | 7000 | − | 5000 | ) |
| 180 | ( | x | − | 5000 | ) | − | 100 | ( | x | − | 5000 | ) | ÷ | ( | 7000 | − | 5000 | ) | × | ( | 7000 | − | 5000 | ) | = | 0 |
| 180 | x | − | 180 | × | 5000 | − | 100 | ( | x | − | 5000 | ) | ÷ | ( | 7000 | − | 5000 | ) | × | ( | 7000 | − | 5000 | ) | = | 0 |
| 180 | x | − | 900000 | − | 100 | ( | x | − | 5000 | ) | ÷ | ( | 7000 | − | 5000 | ) | × | ( | 7000 | − | 5000 | ) | = | 0 |
| 方程两边同时乘以: | ( | 7000 | − | 5000 | ) |
| 180 | x | ( | 7000 | − | 5000 | ) | − | 900000 | ( | 7000 | − | 5000 | ) | − | 100 | ( | x | − | 5000 | ) | ( | 7000 | − | 5000 | ) | = | 0 |
| 180 | x | × | 7000 | − | 180 | x | × | 5000 | − | 900000 | ( | 7000 | − | 5000 | ) | − | 100 | ( | x | − | 5000 | ) | ( | 7000 | − | 5000 | ) | = | 0 |
| 1260000 | x | − | 900000 | x | − | 900000 | ( | 7000 | − | 5000 | ) | − | 100 | ( | x | − | 5000 | ) | ( | 7000 | − | 5000 | ) | = | 0 |
| 360000 | x | − | 900000 | ( | 7000 | − | 5000 | ) | − | 100 | ( | x | − | 5000 | ) | ( | 7000 | − | 5000 | ) | = | 0 |
| 360000 | x | − | 900000 | × | 7000 | + | 900000 | × | 5000 | − | 100 | ( | x | − | 5000 | ) | ( | 7000 | − | 5000 | ) | = | 0 |
| 360000 | x | − | 6300000000 | + | 4500000000 | − | 100 | ( | x | − | 5000 | ) | ( | 7000 | − | 5000 | ) | = | 0 |
| 360000 | x | − | 1800000000 | − | 100 | ( | x | − | 5000 | ) | ( | 7000 | − | 5000 | ) | = | 0 |
| 360000 | x | − | 1800000000 | − | 100 | x | ( | 7000 | − | 5000 | ) | + | 100 | × | 5000 | ( | 7000 | − | 5000 | ) | = | 0 |
| 360000 | x | − | 1800000000 | − | 100 | x | ( | 7000 | − | 5000 | ) | + | 500000 | ( | 7000 | − | 5000 | ) | = | 0 |
| 360000 | x | − | 1800000000 | − | 100 | x | × | 7000 | + | 100 | x | × | 5000 | + | 500000 | ( | 7000 | − | 5000 | ) | = | 0 |
| 360000 | x | − | 1800000000 | − | 700000 | x | + | 500000 | x | + | 500000 | ( | 7000 | − | 5000 | ) | = | 0 |
| 160000 | x | − | 1800000000 | + | 500000 | ( | 7000 | − | 5000 | ) | = | 0 |
| 160000 | x | − | 1800000000 | + | 500000 | × | 7000 | − | 500000 | × | 5000 | = | 0 |
| 160000 | x | − | 1800000000 | + | 3500000000 | − | 2500000000 | = | 0 |
| 160000 | x | − | 800000000 | = | 0 |
| 160000 | x | = | 0 | + | 800000000 |
| 160000 | x | = | 800000000 |
| x | = | 800000000 | ÷ | 160000 |
| = | 800000000 | × | 1 160000 |
| = | 5000 | × | 1 |
| x | = | 5000 |