| ( | 287 5 | × | 200 | + | 0 | ) | ÷ | ( | 100 | + | x | ) | = | 13 |
| 方程两边同时乘以: | ( | 100 | + | x | ) |
| ( | 287 5 | × | 200 | + | 0 | ) | = | 13 | ( | 100 | + | x | ) |
287 5 | × | 200 | + | 0 | = | 13 | ( | 100 | + | x | ) |
287 5 | × | 200 | + | 0 | = | 13 | × | 100 | + | 13 | x |
| 11480 | + | 0 | = | 1300 | + | 13 | x |
| 11480 | = | 1300 | + | 13 | x |
| - | 13 | x | = | 1300 | − | 11480 |
| - | 13 | x | = | - | 10180 |
| 10180 | = | 13 | x |
| 13 | x | = | 10180 |
| x | = | 10180 | ÷ | 13 |
| = | 10180 | × | 1 13 |
| x | = | 10180 13 |
| x | = | 783.076923 |