| ( | 40 | − | x | ) | × | 5 | = | ( | 60 | − | x | ) | × | 9 |
| Left side of the equation = | 40 | × | 5 | − | x | × | 5 |
| = | 200 | − | x | × | 5 |
| 200 | − | 5 | x | = | ( | 60 | − | x | ) | × | 9 |
| Right side of the equation = | 60 | × | 9 | − | x | × | 9 |
| = | 540 | − | x | × | 9 |
| 200 | − | 5 | x | = | 540 | − | 9 | x |
| - | 5 | x | + | 9 | x | = | 540 | − | 200 |
| 4 | x | = | 540 | − | 200 |
| 4 | x | = | 340 |
| x | = | 340 | ÷ | 4 |
| = | 340 | × | 1 4 |
| = | 85 | × | 1 |
| x | = | 85 |