( | 50 | − | x | ) | ( | 500 | + | 20 | x | ) | = | 28000 |
Left side of the equation = | 50 | ( | 500 | + | 20 | x | ) | − | x | ( | 500 | + | 20 | x | ) |
= | 50 | × | 500 | + | 50 | × | 20 | x | − | x | ( | 500 | + | 20 | x | ) |
= | 25000 | + | 1000 | x | − | x | ( | 500 | + | 20 | x | ) |
= | 25000 | + | 1000 | x | − | x | × | 500 | − | x | × | 20 | x |
= | 25000 | + | 500 | x | − | x | × | 20 | x |
25000 | + | 500 | x | − | x | × | 20 | x | = | 28000 |