| ( | 19 | ÷ | 4 | ) | ÷ | ( | 45 | a | ÷ | 7 | + | 15 | a | ÷ | 4 | ) | = | 5 2 | a | ÷ | ( | 60 | a | ÷ | 7 | ) |
| 方程两边同时乘以: | ( | 45 | a | ÷ | 7 | + | 15 | a | ÷ | 4 | ) | , | ( | 60 | × | 1 | ÷ | 7 | ) |
| ( | 19 | ÷ | 4 | ) | ( | 60 | × | 1 | ÷ | 7 | ) | = | 5 2 | × | 1 | ( | 45 | a | ÷ | 7 | + | 15 | a | ÷ | 4 | ) |
| 19 | ÷ | 4 | × | ( | 60 | × | 1 | ÷ | 7 | ) | = | 5 2 | × | 1 | ( | 45 | a | ÷ | 7 | + | 15 | a | ÷ | 4 | ) |
| 19 | ÷ | 4 | × | ( | 60 | × | 1 | ÷ | 7 | ) | = | 5 2 | × | 1 | × | 45 | a | ÷ | 7 | + | 5 2 | × | 1 | × | 15 | a | ÷ | 4 |
19 4 | ( | 60 | × | 1 | ÷ | 7 | ) | = | 225 14 | a | + | 75 8 | a |
19 4 | ( | 60 | × | 1 | ÷ | 7 | ) | = | 1425 56 | a |
19 4 | × | 60 | × | 1 | ÷ | 7 | = | 1425 56 | a |
285 7 | = | 1425 56 | a |
| - | 1425 56 | a | = | - | 285 7 |
285 7 | = | 1425 56 | a |
1425 56 | a | = | 285 7 |
| a | = | 285 7 | ÷ | 1425 56 |
| = | 285 7 | × | 56 1425 |
| = | 1 | × | 8 5 |
| a | = | 8 5 |
| a | = | 1.6 |