120 | ( | 1 | + | x | ) | ( | 1 | + | x | ) | = | 570 |
Left side of the equation = | 120 | × | 1 | ( | 1 | + | x | ) | + | 120 | x | ( | 1 | + | x | ) |
= | 120 | ( | 1 | + | x | ) | + | 120 | x | ( | 1 | + | x | ) |
= | 120 | × | 1 | + | 120 | x | + | 120 | x | ( | 1 | + | x | ) |
= | 120 | + | 120 | x | + | 120 | x | ( | 1 | + | x | ) |
= | 120 | + | 120 | x | + | 120 | x | × | 1 | + | 120 | x | x |
= | 120 | + | 120 | x | + | 120 | x | + | 120 | x | x |
= | 120 | + | 240 | x | + | 120 | x | x |
120 | + | 240 | x | + | 120 | x | x | = | 570 |