30 | ( | t | − | 10 | ) | ÷ | 60 | − | 20 | ( | t | + | 12 | ) | ÷ | 60 | = | 0 |
方程左边 = | 1 2 | ( | t | − | 10 | ) | − | 1 3 | ( | t | + | 12 | ) |
1 2 | ( | t | − | 10 | ) | − | 1 3 | ( | t | + | 12 | ) | = | 0 |
方程左边 = | 1 2 | t | − | 1 2 | × | 10 | − | 1 3 | ( | t | + | 12 | ) |
= | 1 2 | t | − | 5 | − | 1 3 | ( | t | + | 12 | ) |
= | 1 2 | t | − | 5 | − | 1 3 | t | − | 1 3 | × | 12 |
= | 1 2 | t | − | 5 | − | 1 3 | t | − | 4 |
= | 1 6 | t | − | 9 |
1 6 | t | − | 9 | = | 0 |
1 6 | t | = | 0 | + | 9 |
1 6 | t | = | 9 |
t | = | 9 | ÷ | 1 6 |
= | 9 | × | 6 |
t | = | 54 |