| ( | 5 | x | + | 51 | ) | ÷ | ( | x | + | 17 | ) | = | 19 4 |
| 方程两边同时乘以: | ( | x | + | 17 | ) |
| ( | 5 | x | + | 51 | ) | = | 19 4 | ( | x | + | 17 | ) |
| 5 | x | + | 51 | = | 19 4 | ( | x | + | 17 | ) |
| 5 | x | + | 51 | = | 19 4 | x | + | 19 4 | × | 17 |
| 5 | x | + | 51 | = | 19 4 | x | + | 323 4 |
| 5 | x | − | 19 4 | x | = | 323 4 | − | 51 |
1 4 | x | = | 323 4 | − | 51 |
1 4 | x | = | 119 4 |
| x | = | 119 4 | ÷ | 1 4 |
| = | 119 4 | × | 4 |
| = | 119 | × | 1 |
| x | = | 119 |