| ( | x | + | 20 100 | x | ) | × | 80 100 | = | x | × | 400 |
| Left side of the equation = | x | × | 80 100 | + | 20 100 | x | × | 80 100 |
| = | x | × | 80 100 | + | 4 25 | x |
| = | 24 25 | x |
24 25 | x | = | x | × | 400 |
24 25 | x | − | 400 | x | = | 0 |
| - | 9976 25 | x | = | 0 |
| - | 0 | = | 9976 25 | x |
9976 25 | x | = | - | 0 |
| x | = | - | 0 | ÷ | 9976 25 |
| = | - | 0 | × | 25 9976 |
| x | = | 0 |