| ( | 400 | − | 10 | A | ) | ( | 6 | + | 1 2 | A | ) | − | 40 | A | = | 1175 |
| Left side of the equation = | 400 | ( | 6 | + | 1 2 | A | ) | − | 10 | A | ( | 6 | + | 1 2 | A | ) | − | 40 | A |
| = | 400 | × | 6 | + | 400 | × | 1 2 | A | − | 10 | A | ( | 6 | + | 1 2 | A | ) | − | 40 | A |
| = | 2400 | + | 200 | A | − | 10 | A | ( | 6 | + | 1 2 | A | ) | − | 40 | A |
| = | 2400 | + | 160 | A | − | 10 | A | ( | 6 | + | 1 2 | A | ) |
| = | 2400 | + | 160 | A | − | 10 | A | × | 6 | − | 10 | A | × | 1 2 | A |
| = | 2400 | + | 160 | A | − | 60 | A | − | 5 | A | A |
| = | 2400 | + | 100 | A | − | 5 | A | A |
| 2400 | + | 100 | A | − | 5 | A | A | = | 1175 |