| x | = | 7800000 | ÷ | ( | ( | 40 | + | 4 | ) | × | 10 | ) |
| 方程两边同时乘以: | ( | ( | 40 | + | 4 | ) | × | 10 | ) |
| x | ( | ( | 40 | + | 4 | ) | × | 10 | ) | = | 7800000 |
| x | ( | 40 | + | 4 | ) | × | 10 | = | 7800000 |
| x | × | 40 | × | 10 | + | x | × | 4 | × | 10 | = | 7800000 |
| x | × | 400 | + | x | × | 40 | = | 7800000 |
| 440 | x | = | 7800000 |
| x | = | 7800000 | ÷ | 440 |
| = | 7800000 | × | 1 440 |
| = | 195000 | × | 1 11 |
| x | = | 195000 11 |
| x | = | 17727.272727 |