| ( | Y | + | 495 | ) | ÷ | ( | Y | + | 791 | ) | = | 3 4 |
| 方程两边同时乘以: | ( | Y | + | 791 | ) |
| ( | Y | + | 495 | ) | = | 3 4 | ( | Y | + | 791 | ) |
| Y | + | 495 | = | 3 4 | ( | Y | + | 791 | ) |
| Y | + | 495 | = | 3 4 | Y | + | 3 4 | × | 791 |
| Y | + | 495 | = | 3 4 | Y | + | 2373 4 |
| Y | − | 3 4 | Y | = | 2373 4 | − | 495 |
1 4 | Y | = | 2373 4 | − | 495 |
1 4 | Y | = | 393 4 |
| Y | = | 393 4 | ÷ | 1 4 |
| = | 393 4 | × | 4 |
| = | 393 | × | 1 |
| Y | = | 393 |