( | 12 | − | 2 | t | ) | ( | 24 | − | 4 | t | ) | = | 40 |
方程左边 = | 12 | ( | 24 | − | 4 | t | ) | − | 2 | t | ( | 24 | − | 4 | t | ) |
= | 12 | × | 24 | − | 12 | × | 4 | t | − | 2 | t | ( | 24 | − | 4 | t | ) |
= | 288 | − | 48 | t | − | 2 | t | ( | 24 | − | 4 | t | ) |
= | 288 | − | 48 | t | − | 2 | t | × | 24 | + | 2 | t | × | 4 | t |
= | 288 | − | 48 | t | − | 48 | t | + | 8 | t | t |
= | 288 | − | 96 | t | + | 8 | t | t |
288 | − | 96 | t | + | 8 | t | t | = | 40 |