Evaluate
-7\sqrt{5}-13\approx -28.652475842
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\left(\sqrt{5}\right)^{2}-9\sqrt{5}+2\sqrt{5}-18
Apply the distributive property by multiplying each term of \sqrt{5}+2 by each term of \sqrt{5}-9.
5-9\sqrt{5}+2\sqrt{5}-18
The square of \sqrt{5} is 5.
5-7\sqrt{5}-18
Combine -9\sqrt{5} and 2\sqrt{5} to get -7\sqrt{5}.
-13-7\sqrt{5}
Subtract 18 from 5 to get -13.
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