| ( | 1 | − | 1000 | x | ) | ( | 4 5 | + | 800 | x | ) | = | ( | 4 | − | 500 | x | ) | ( | 9 10 | − | 800 | x | ) |
| Left side of the equation = | 1 | ( | 4 5 | + | 800 | x | ) | − | 1000 | x | ( | 4 5 | + | 800 | x | ) |
| = | 1 | × | 4 5 | + | 1 | × | 800 | x | − | 1000 | x | ( | 4 5 | + | 800 | x | ) |
| = | 4 5 | + | 800 | x | − | 1000 | x | ( | 4 5 | + | 800 | x | ) |
| = | 4 5 | + | 800 | x | − | 1000 | x | × | 4 5 | − | 1000 | x | × | 800 | x |
| = | 4 5 | + | 800 | x | − | 800 | x | − | 800000 | x | x |
| = | 4 5 | + | 0 | x | − | 800000 | x | x |
4 5 | + | 0 | x | − | 800000 | x | x | = | ( | 4 | − | 500 | x | ) | ( | 9 10 | − | 800 | x | ) |
| Right side of the equation = | 4 | ( | 9 10 | − | 800 | x | ) | − | 500 | x | ( | 9 10 | − | 800 | x | ) |
| = | 4 | × | 9 10 | − | 4 | × | 800 | x | − | 500 | x | ( | 9 10 | − | 800 | x | ) |
| = | 18 5 | − | 3200 | x | − | 500 | x | ( | 9 10 | − | 800 | x | ) |
| = | 18 5 | − | 3200 | x | − | 500 | x | × | 9 10 | + | 500 | x | × | 800 | x |
| = | 18 5 | − | 3200 | x | − | 450 | x | + | 400000 | x | x |
| = | 18 5 | − | 3650 | x | + | 400000 | x | x |
4 5 | − | 800000 | x | x | = | 18 5 | − | 3650 | x | + | 400000 | x | x |