| 7 | ( | 3 | ÷ | 4 | − | k | ) | = | 24 | ( | 1 | + | 3 | k | ÷ | 4 | ) |
| 方程左边 = | 7 | × | 3 | ÷ | 4 | − | 7 | k |
| = | 21 4 | − | 7 | k |
21 4 | − | 7 | k | = | 24 | ( | 1 | + | 3 | k | ÷ | 4 | ) |
| 方程右边 = | 24 | × | 1 | + | 24 | × | 3 | k | ÷ | 4 |
| = | 24 | + | 18 | k |
21 4 | − | 7 | k | = | 24 | + | 18 | k |
| - | 7 | k | − | 18 | k | = | 24 | − | 21 4 |
| - | 25 | k | = | 24 | − | 21 4 |
| - | 25 | k | = | 75 4 |
| - | 75 4 | = | 25 | k |
| 25 | k | = | - | 75 4 |
| k | = | - | 75 4 | ÷ | 25 |
| = | - | 75 4 | × | 1 25 |
| = | - | 3 4 | × | 1 |
| k | = | - | 3 4 |
| k | = | - 0.75 |