( | 16 | − | a | ) | ( | 100 | + | 10 | a | ) | = | 1200 |
Left side of the equation = | 16 | ( | 100 | + | 10 | a | ) | − | a | ( | 100 | + | 10 | a | ) |
= | 16 | × | 100 | + | 16 | × | 10 | a | − | a | ( | 100 | + | 10 | a | ) |
= | 1600 | + | 160 | a | − | a | ( | 100 | + | 10 | a | ) |
= | 1600 | + | 160 | a | − | a | × | 100 | − | a | × | 10 | a |
= | 1600 | + | 60 | a | − | a | × | 10 | a |
1600 | + | 60 | a | − | a | × | 10 | a | = | 1200 |