| ( | x | − | 90 | ) | × | 3 4 | ÷ | 100 | = | 0 |
| Left side of the equation = | ( | x | − | 90 | ) | × | 3 400 |
| ( | x | − | 90 | ) | × | 3 400 | = | 0 |
| Left side of the equation = | x | × | 3 400 | − | 90 | × | 3 400 |
| = | x | × | 3 400 | − | 27 40 |
3 400 | x | − | 27 40 | = | 0 |
3 400 | x | = | 0 | + | 27 40 |
3 400 | x | = | 27 40 |
| x | = | 27 40 | ÷ | 3 400 |
| = | 27 40 | × | 400 3 |
| = | 9 | × | 10 |
| x | = | 90 |