Evaluate
11-4\sqrt{7}\approx 0.416994756
Expand
11-4\sqrt{7}
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\left(\sqrt{7}\right)^{2}-4\sqrt{7}+4
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(\sqrt{7}-2\right)^{2}.
7-4\sqrt{7}+4
The square of \sqrt{7} is 7.
11-4\sqrt{7}
Add 7 and 4 to get 11.
\left(\sqrt{7}\right)^{2}-4\sqrt{7}+4
Use binomial theorem \left(a-b\right)^{2}=a^{2}-2ab+b^{2} to expand \left(\sqrt{7}-2\right)^{2}.
7-4\sqrt{7}+4
The square of \sqrt{7} is 7.
11-4\sqrt{7}
Add 7 and 4 to get 11.
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