| ( | 68 | − | 58 | ) | ÷ | ( | 58 | − | 40 | ) | = | ( | 85 | − | t | ) | ÷ | ( | t | − | 71 | ) |
| Multiply both sides of the equation by: | ( | 58 | − | 40 | ) | , | ( | t | − | 71 | ) |
| ( | 68 | − | 58 | ) | ( | t | − | 71 | ) | = | ( | 85 | − | t | ) | ( | 58 | − | 40 | ) |
| 68 | ( | t | − | 71 | ) | − | 58 | ( | t | − | 71 | ) | = | ( | 85 | − | t | ) | ( | 58 | − | 40 | ) |
| 68 | ( | t | − | 71 | ) | − | 58 | ( | t | − | 71 | ) | = | 85 | ( | 58 | − | 40 | ) | − | t | ( | 58 | − | 40 | ) |
| 68 | t | − | 68 | × | 71 | − | 58 | ( | t | − | 71 | ) | = | 85 | ( | 58 | − | 40 | ) | − | t | ( | 58 | − | 40 | ) |
| 68 | t | − | 68 | × | 71 | − | 58 | ( | t | − | 71 | ) | = | 85 | × | 58 | − | 85 | × | 40 | − | t | ( | 58 | − | 40 | ) |
| 68 | t | − | 4828 | − | 58 | ( | t | − | 71 | ) | = | 4930 | − | 3400 | − | t | ( | 58 | − | 40 | ) |
| 68 | t | − | 4828 | − | 58 | ( | t | − | 71 | ) | = | 1530 | − | t | ( | 58 | − | 40 | ) |
| 68 | t | − | 4828 | − | 58 | t | + | 58 | × | 71 | = | 1530 | − | t | ( | 58 | − | 40 | ) |
| 68 | t | − | 4828 | − | 58 | t | + | 58 | × | 71 | = | 1530 | − | t | × | 58 | + | t | × | 40 |
| 68 | t | − | 4828 | − | 58 | t | + | 4118 | = | 1530 | − | t | × | 58 | + | t | × | 40 |
| 10 | t | − | 710 | = | 1530 | − | 18 | t |
| 10 | t | + | 18 | t | = | 1530 | + | 710 |
| 28 | t | = | 1530 | + | 710 |
| 28 | t | = | 2240 |
| t | = | 2240 | ÷ | 28 |
| = | 2240 | × | 1 28 |
| = | 80 | × | 1 |
| t | = | 80 |