Evaluate
15\sqrt{7}\approx 39.686269666
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\sqrt{7}+2\times 3\sqrt{7}+4\sqrt{28}
Factor 63=3^{2}\times 7. Rewrite the square root of the product \sqrt{3^{2}\times 7} as the product of square roots \sqrt{3^{2}}\sqrt{7}. Take the square root of 3^{2}.
\sqrt{7}+6\sqrt{7}+4\sqrt{28}
Multiply 2 and 3 to get 6.
7\sqrt{7}+4\sqrt{28}
Combine \sqrt{7} and 6\sqrt{7} to get 7\sqrt{7}.
7\sqrt{7}+4\times 2\sqrt{7}
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}.
7\sqrt{7}+8\sqrt{7}
Multiply 4 and 2 to get 8.
15\sqrt{7}
Combine 7\sqrt{7} and 8\sqrt{7} to get 15\sqrt{7}.
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