| 0 | ( | 40 | − | t | ) | = | 2 | ( | t | − | 30 | ) |
| Left side of the equation = | 0 | × | 40 | − | 0 | t |
| = | 0 | − | 0 | t |
| 0 | − | 0 | t | = | 2 | ( | t | − | 30 | ) |
| Right side of the equation = | 2 | t | − | 2 | × | 30 |
| = | 2 | t | − | 60 |
| - | 0 | = | 2 | t | − | 60 |
| - | 2 | t | = | - | 60 | + | 0 |
| - | 2 | t | = | - | 60 |
| 60 | = | 2 | t |
| 2 | t | = | 60 |
| t | = | 60 | ÷ | 2 |
| = | 60 | × | 1 2 |
| = | 30 | × | 1 |
| t | = | 30 |