| 400 | ÷ | ( | 643 10 | − | x | ) | = | 150 | ( | 1653 10 | − | x | ) |
| Multiply both sides of the equation by: | ( | 643 10 | − | x | ) |
| 400 | = | 150 | ( | 1653 10 | − | x | ) | ( | 643 10 | − | x | ) |
| 400 | = | 150 | × | 1653 10 | ( | 643 10 | − | x | ) | − | 150 | x | ( | 643 10 | − | x | ) |
| 400 | = | 24795 | ( | 643 10 | − | x | ) | − | 150 | x | ( | 643 10 | − | x | ) |
| 400 | = | 24795 | × | 643 10 | − | 24795 | x | − | 150 | x | ( | 643 10 | − | x | ) |
| 400 | = | 3188637 2 | − | 24795 | x | − | 150 | x | ( | 643 10 | − | x | ) |
| 400 | = | 3188637 2 | − | 24795 | x | − | 150 | x | × | 643 10 | + | 150 | x | x |
| 400 | = | 3188637 2 | − | 24795 | x | − | 9645 | x | + | 150 | x | x |
| 400 | = | 3188637 2 | − | 34440 | x | + | 150 | x | x |