( | 400 | − | x | ) | ( | 8 | + | x | ÷ | 10 | ) | = | 5600 |
Left side of the equation = | 400 | ( | 8 | + | x | ÷ | 10 | ) | − | x | ( | 8 | + | x | ÷ | 10 | ) |
= | 400 | × | 8 | + | 400 | x | ÷ | 10 | − | x | ( | 8 | + | x | ÷ | 10 | ) |
= | 3200 | + | 40 | x | − | x | ( | 8 | + | x | ÷ | 10 | ) |
= | 3200 | + | 40 | x | − | x | × | 8 | − | x | x | ÷ | 10 |
= | 3200 | + | 32 | x | − | x | x | × | 1 10 |
3200 | + | 32 | x | − | x | x | × | 1 10 | = | 5600 |