| 100 | × | 217 10 | + | x | × | 30 | = | ( | 100 | + | x | ) | × | 25 |
| Left side of the equation = | 2170 | + | x | × | 30 |
| 2170 | + | 30 | x | = | ( | 100 | + | x | ) | × | 25 |
| Right side of the equation = | 100 | × | 25 | + | x | × | 25 |
| = | 2500 | + | x | × | 25 |
| 2170 | + | 30 | x | = | 2500 | + | 25 | x |
| 30 | x | − | 25 | x | = | 2500 | − | 2170 |
| 5 | x | = | 2500 | − | 2170 |
| 5 | x | = | 330 |
| x | = | 330 | ÷ | 5 |
| = | 330 | × | 1 5 |
| = | 66 | × | 1 |
| x | = | 66 |