( | 16 | − | x | ) | ( | 160 | + | 40 | x | ) | = | 3640 |
Left side of the equation = | 16 | ( | 160 | + | 40 | x | ) | − | x | ( | 160 | + | 40 | x | ) |
= | 16 | × | 160 | + | 16 | × | 40 | x | − | x | ( | 160 | + | 40 | x | ) |
= | 2560 | + | 640 | x | − | x | ( | 160 | + | 40 | x | ) |
= | 2560 | + | 640 | x | − | x | × | 160 | − | x | × | 40 | x |
= | 2560 | + | 480 | x | − | x | × | 40 | x |
2560 | + | 480 | x | − | x | × | 40 | x | = | 3640 |