Evaluate
21
Factor
3\times 7
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\sqrt{7}\left(\sqrt{7}+2\sqrt{7}\right)
Factor 28=2^{2}\times 7. Rewrite the square root of the product \sqrt{2^{2}\times 7} as the product of square roots \sqrt{2^{2}}\sqrt{7}. Take the square root of 2^{2}.
\sqrt{7}\times 3\sqrt{7}
Combine \sqrt{7} and 2\sqrt{7} to get 3\sqrt{7}.
7\times 3
Multiply \sqrt{7} and \sqrt{7} to get 7.
21
Multiply 7 and 3 to get 21.
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