Add and subtract radicals quick check add three with the square root of 21+7 with the square root of 21 with the answer be square root 24+ square root 28 or 10 square root of 42 or 10 with the square root of 21 or square root of 52

Answer 1

To solve the expression you provided, we'll break it down step by step.

1. Adding the radicals:

   • You have two terms with \(\sqrt{21}\): \[ 3\sqrt{21} + 7\sqrt{21} = (3 + 7)\sqrt{21} = 10\sqrt{21} \]

2. You want to check against the provided answers:

   • \(\sqrt{24}\) and \(\sqrt{28}\) can be simplified but they don't directly relate to this calculation.
   • \(10\sqrt{42}\) doesn't apply since we're working only with \(\sqrt{21}\).
   • \(10\sqrt{21}\) is correct as calculated.
   • \(\sqrt{52}\) does not relate since it involves a different radical.

Thus, the correct answer from your calculations for \(3\sqrt{21} + 7\sqrt{21}\) is:

\[ 10\sqrt{21} \]

This is your final answer. Would you like help with any more calculations involving radicals?