| ( | a | + | 3 | ) | × | 2 | ÷ | 3 | = | a | × | 4 | ÷ | 5 |
| 方程左边 = | ( | a | + | 3 | ) | × | 2 3 |
| ( | a | + | 3 | ) | × | 2 3 | = | a | × | 4 | ÷ | 5 |
| 方程左边 = | a | × | 2 3 | + | 3 | × | 2 3 |
| = | a | × | 2 3 | + | 2 |
2 3 | a | + | 2 | = | a | × | 4 | ÷ | 5 |
| 方程右边 = | a | × | 4 5 |
2 3 | a | + | 2 | = | 4 5 | a |
2 3 | a | − | 4 5 | a | = | - | 2 |
| - | 2 15 | a | = | - | 2 |
| 2 | = | 2 15 | a |
2 15 | a | = | 2 |
| a | = | 2 | ÷ | 2 15 |
| = | 2 | × | 15 2 |
| = | 1 | × | 15 |
| a | = | 15 |