Evaluate
17-4\sqrt{13}\approx 2.577794898
Expand
17-4\sqrt{13}
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4-4\sqrt{13}+\left(\sqrt{13}\right)^{2}
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(2-\sqrt{13}\right)^{2}.
4-4\sqrt{13}+13
The square of \sqrt{13} is 13.
17-4\sqrt{13}
Add 4 and 13 to get 17.
4-4\sqrt{13}+\left(\sqrt{13}\right)^{2}
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(2-\sqrt{13}\right)^{2}.
4-4\sqrt{13}+13
The square of \sqrt{13} is 13.
17-4\sqrt{13}
Add 4 and 13 to get 17.
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