Evaluate
50-20\sqrt{5}\approx 5.27864045
Factor
10 \sqrt{5} {(\sqrt{5} - 2)} = 5.27864045
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-20\sqrt{5}+10\left(\sqrt{5}\right)^{2}
Use the distributive property to multiply 5\sqrt{5} by -4+2\sqrt{5}.
-20\sqrt{5}+10\times 5
The square of \sqrt{5} is 5.
-20\sqrt{5}+50
Multiply 10 and 5 to get 50.
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Limits
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