19 20 | ÷ | ( | 19 20 | + | X | ) | = | 3 4 |
| 方程两边同时乘以: | ( | 19 20 | + | X | ) |
19 20 | = | 3 4 | ( | 19 20 | + | X | ) |
19 20 | = | 3 4 | × | 19 20 | + | 3 4 | X |
19 20 | = | 57 80 | + | 3 4 | X |
| - | 3 4 | X | = | 57 80 | − | 19 20 |
| - | 3 4 | X | = | - | 19 80 |
19 80 | = | 3 4 | X |
3 4 | X | = | 19 80 |
| X | = | 19 80 | ÷ | 3 4 |
| = | 19 80 | × | 4 3 |
| = | 19 20 | × | 1 3 |
| X | = | 19 60 |
| X | = | 0.316667 |