| ( | 30 | × | 3 20 | + | 50 | x | ) | ÷ | ( | 30 | + | 50 | ) | = | 1 5 |
| 方程两边同时乘以: | ( | 30 | + | 50 | ) |
| ( | 30 | × | 3 20 | + | 50 | x | ) | = | 1 5 | ( | 30 | + | 50 | ) |
| 30 | × | 3 20 | + | 50 | x | = | 1 5 | ( | 30 | + | 50 | ) |
| 30 | × | 3 20 | + | 50 | x | = | 1 5 | × | 30 | + | 1 5 | × | 50 |
9 2 | + | 50 | x | = | 6 | + | 10 |
9 2 | + | 50 | x | = | 16 |
| 50 | x | = | 16 | − | 9 2 |
| 50 | x | = | 23 2 |
| x | = | 23 2 | ÷ | 50 |
| = | 23 2 | × | 1 50 |
| x | = | 23 100 |
| x | = | 0.23 |