( | 19 | − | x | ) | ( | 300 | + | 30 | x | ) | = | 6300 |
Left side of the equation = | 19 | ( | 300 | + | 30 | x | ) | − | x | ( | 300 | + | 30 | x | ) |
= | 19 | × | 300 | + | 19 | × | 30 | x | − | x | ( | 300 | + | 30 | x | ) |
= | 5700 | + | 570 | x | − | x | ( | 300 | + | 30 | x | ) |
= | 5700 | + | 570 | x | − | x | × | 300 | − | x | × | 30 | x |
= | 5700 | + | 270 | x | − | x | × | 30 | x |
5700 | + | 270 | x | − | x | × | 30 | x | = | 6300 |