600 | = | ( | - | 2 | x | + | 130 | ) | ( | x | − | 20 | ) |
Right side of the equation = | - | 2 | x | ( | x | − | 20 | ) | + | 130 | ( | x | − | 20 | ) |
= | - | 2 | x | x | + | 2 | x | × | 20 | + | 130 | ( | x | − | 20 | ) |
= | - | 2 | x | x | + | 40 | x | + | 130 | ( | x | − | 20 | ) |
= | - | 2 | x | x | + | 40 | x | + | 130 | x | − | 130 | × | 20 |
= | - | 2 | x | x | + | 40 | x | + | 130 | x | − | 2600 |
= | - | 2 | x | x | + | 170 | x | − | 2600 |
600 | = | - | 2 | x | x | + | 170 | x | − | 2600 |