| ( | 42 | + | 50 | + | X | ) | ÷ | 3 | × | 1 2 | + | ( | X | × | 1 2 | ) | = | 50 |
| 方程左边 = | ( | 42 | + | 50 | + | X | ) | × | 1 6 | + | ( | X | × | 1 2 | ) |
| ( | 42 | + | 50 | + | X | ) | × | 1 6 | + | ( | X | × | 1 2 | ) | = | 50 |
| 方程左边 = | 42 | × | 1 6 | + | 50 | × | 1 6 | + | X | × | 1 6 | + | ( | X | × | 1 2 | ) |
| = | 7 | + | 25 3 | + | X | × | 1 6 | + | ( | X | × | 1 2 | ) |
| = | 46 3 | + | 1 6 | X | + | ( | X | × | 1 2 | ) |
| = | 46 3 | + | 1 6 | X | + | X | × | 1 2 |
| = | 46 3 | + | 2 3 | X |
46 3 | + | 2 3 | X | = | 50 |
2 3 | X | = | 50 | − | 46 3 |
2 3 | X | = | 104 3 |
| X | = | 104 3 | ÷ | 2 3 |
| = | 104 3 | × | 3 2 |
| = | 52 | × | 1 |
| X | = | 52 |