| ( | 117 100 | ( | a | − | 100 | ) | − | ( | a | − | 100 | ) | ) | + | ( | 27 25 | a | − | a | ) | = | 40 |
| Left side of the equation = | 117 100 | ( | a | − | 100 | ) | − | ( | a | − | 100 | ) | + | ( | 27 25 | a | − | a | ) |
| = | 117 100 | a | − | 117 100 | × | 100 | − | ( | a | − | 100 | ) | + | ( | 27 25 | a | − | a | ) |
| = | 117 100 | a | − | 117 | − | ( | a | − | 100 | ) | + | ( | 27 25 | a | − | a | ) |
| = | 117 100 | a | − | 117 | − | a | + | 100 | + | ( | 27 25 | a | − | a | ) |
| = | 17 100 | a | − | 17 | + | ( | 27 25 | a | − | a | ) |
| = | 17 100 | a | − | 17 | + | 27 25 | a | − | a |
| = | 1 4 | a | − | 17 |
1 4 | a | − | 17 | = | 40 |
1 4 | a | = | 40 | + | 17 |
1 4 | a | = | 57 |
| a | = | 57 | ÷ | 1 4 |
| = | 57 | × | 4 |
| a | = | 228 |