| 16 | + | ( | 4 | + | x | ) | ( | 4 | + | x | ) | ÷ | 9 | = | x | x |
| Left side of the equation = | 16 | + | 4 | ( | 4 | + | x | ) | × | 1 9 | + | x | ( | 4 | + | x | ) | × | 1 9 |
| = | 16 | + | 4 9 | ( | 4 | + | x | ) | + | x | ( | 4 | + | x | ) | × | 1 9 |
| = | 16 | + | 4 9 | × | 4 | + | 4 9 | x | + | x | ( | 4 | + | x | ) | × | 1 9 |
| = | 16 | + | 16 9 | + | 4 9 | x | + | x | ( | 4 | + | x | ) | × | 1 9 |
| = | 160 9 | + | 4 9 | x | + | x | ( | 4 | + | x | ) | × | 1 9 |
| = | 160 9 | + | 4 9 | x | + | x | × | 4 | × | 1 9 | + | x | x | × | 1 9 |
| = | 160 9 | + | 4 9 | x | + | x | × | 4 9 | + | x | x | × | 1 9 |
| = | 160 9 | + | 8 9 | x | + | x | x | × | 1 9 |
160 9 | + | 8 9 | x | + | x | x | × | 1 9 | = | x | x |