| 40 | × | 45 | ( | 1 | − | 1 100 | x | ) | + | 20 | ( | 1 | − | 1 100 | x | ) | ( | 40 | + | 2 | x | ) | = | 2600 |
| Left side of the equation = | 1800 | ( | 1 | − | 1 100 | x | ) | + | 20 | ( | 1 | − | 1 100 | x | ) | ( | 40 | + | 2 | x | ) |
| 1800 | ( | 1 | − | 1 100 | x | ) | + | 20 | ( | 1 | − | 1 100 | x | ) | ( | 40 | + | 2 | x | ) | = | 2600 |
| Left side of the equation = | 1800 | × | 1 | − | 1800 | × | 1 100 | x | + | 20 | ( | 1 | − | 1 100 | x | ) | ( | 40 | + | 2 | x | ) |
| = | 1800 | − | 18 | x | + | 20 | ( | 1 | − | 1 100 | x | ) | ( | 40 | + | 2 | x | ) |
| = | 1800 | − | 18 | x | + | 20 | × | 1 | ( | 40 | + | 2 | x | ) | − | 20 | × | 1 100 | x | ( | 40 | + | 2 | x | ) |
| = | 1800 | − | 18 | x | + | 20 | ( | 40 | + | 2 | x | ) | − | 1 5 | x | ( | 40 | + | 2 | x | ) |
| = | 1800 | − | 18 | x | + | 20 | × | 40 | + | 20 | × | 2 | x | − | 1 5 | x | ( | 40 | + | 2 | x | ) |
| = | 1800 | − | 18 | x | + | 800 | + | 40 | x | − | 1 5 | x | ( | 40 | + | 2 | x | ) |
| = | 2600 | + | 22 | x | − | 1 5 | x | ( | 40 | + | 2 | x | ) |
| = | 2600 | + | 22 | x | − | 1 5 | x | × | 40 | − | 1 5 | x | × | 2 | x |
| = | 2600 | + | 22 | x | − | 8 | x | − | 2 5 | x | x |
| = | 2600 | + | 14 | x | − | 2 5 | x | x |
| 2600 | + | 14 | x | − | 2 5 | x | x | = | 2600 |