72 | ( | x | − | 21 | ) | + | 72 | ( | x | + | 21 | ) | = | 7 |
Left side of the equation = | 72 | x | − | 72 | × | 21 | + | 72 | ( | x | + | 21 | ) |
= | 72 | x | − | 1512 | + | 72 | ( | x | + | 21 | ) |
= | 72 | x | − | 1512 | + | 72 | x | + | 72 | × | 21 |
= | 72 | x | − | 1512 | + | 72 | x | + | 1512 |
= | 144 | x | − | 0 |
144 | x | − | 0 | = | 7 |
x | = | 7 | ÷ | 144 |
= | 7 | × | 1 144 |
x | = | 7 144 |
x | = | 0.048611 |