| ( | 118 | + | a | ) | ÷ | ( | 132 | + | a | ) | = | 9 10 |
| Multiply both sides of the equation by: | ( | 132 | + | a | ) |
| ( | 118 | + | a | ) | = | 9 10 | ( | 132 | + | a | ) |
| 118 | + | a | = | 9 10 | ( | 132 | + | a | ) |
| 118 | + | a | = | 9 10 | × | 132 | + | 9 10 | a |
| 118 | + | a | = | 594 5 | + | 9 10 | a |
| a | − | 9 10 | a | = | 594 5 | − | 118 |
1 10 | a | = | 594 5 | − | 118 |
1 10 | a | = | 4 5 |
| a | = | 4 5 | ÷ | 1 10 |
| = | 4 5 | × | 10 |
| = | 4 | × | 2 |
| a | = | 8 |