12 | × | 1 50 | × | 325 | ( | 1 | + | 3 25 | a | ) | + | 13 | × | 19 1000 | × | 300 | ( | 1 | − | 1 10 | a | ) | = | 156 |
方程左边 = | 78 | ( | 1 | + | 3 25 | a | ) | + | 741 10 | ( | 1 | − | 1 10 | a | ) |
78 | ( | 1 | + | 3 25 | a | ) | + | 741 10 | ( | 1 | − | 1 10 | a | ) | = | 156 |
方程左边 = | 78 | × | 1 | + | 78 | × | 3 25 | a | + | 741 10 | ( | 1 | − | 1 10 | a | ) |
= | 78 | + | 234 25 | a | + | 741 10 | ( | 1 | − | 1 10 | a | ) |
= | 78 | + | 234 25 | a | + | 741 10 | × | 1 | − | 741 10 | × | 1 10 | a |
= | 78 | + | 234 25 | a | + | 741 10 | − | 741 100 | a |
= | 1521 10 | + | 39 20 | a |
1521 10 | + | 39 20 | a | = | 156 |
39 20 | a | = | 156 | − | 1521 10 |
39 20 | a | = | 39 10 |
a | = | 39 10 | ÷ | 39 20 |
= | 39 10 | × | 20 39 |
= | 1 | × | 2 |
a | = | 2 |