To add or subtract radicals, the degree and radicand must be the same. For example, \(2\sqrt{3} + 3\sqrt{3} = 5\sqrt{3}\) but \(2\sqrt{2} + 2\sqrt{3}\) cannot be added because they have different radicands.
What is \( 4 \)\( \sqrt{63} \) + \( 9 \)\( \sqrt{7} \)
| 21\( \sqrt{7} \) | |
| 13\( \sqrt{63} \) | |
| 36\( \sqrt{7} \) | |
| 13\( \sqrt{441} \) |