| 150 | + | 5 | ( | x | + | 5 | ) | = | 9 10 | ( | 150 | + | 5 | x | ) |
| Left side of the equation = | 150 | + | 5 | x | + | 5 | × | 5 |
| = | 150 | + | 5 | x | + | 25 |
| = | 175 | + | 5 | x |
| 175 | + | 5 | x | = | 9 10 | ( | 150 | + | 5 | x | ) |
| Right side of the equation = | 9 10 | × | 150 | + | 9 10 | × | 5 | x |
| = | 135 | + | 9 2 | x |
| 175 | + | 5 | x | = | 135 | + | 9 2 | x |
| 5 | x | − | 9 2 | x | = | 135 | − | 175 |
1 2 | x | = | 135 | − | 175 |
1 2 | x | = | - | 40 |
| x | = | - | 40 | ÷ | 1 2 |
| = | - | 40 | × | 2 |
| x | = | - | 80 |