Evaluate
54-14\sqrt{5}\approx 22.695048315
Expand
54-14\sqrt{5}
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\left(\sqrt{5}\right)^{2}-14\sqrt{5}+49
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(\sqrt{5}-7\right)^{2}.
5-14\sqrt{5}+49
The square of \sqrt{5} is 5.
54-14\sqrt{5}
Add 5 and 49 to get 54.
\left(\sqrt{5}\right)^{2}-14\sqrt{5}+49
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(\sqrt{5}-7\right)^{2}.
5-14\sqrt{5}+49
The square of \sqrt{5} is 5.
54-14\sqrt{5}
Add 5 and 49 to get 54.
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