\(12-3\sqrt{12}=9-\sqrt{108}+3=9-2\sqrt{27}+3=\left(3-\sqrt{3}\right)^2\)
Bạn ei là hàng đẳng thức \(\left(a-b\right)^2\)??
\(12-3\sqrt{12}=12-3\sqrt{4.3}=12-3.2.\sqrt{3}\)
\(=9-2.3.\sqrt{3}+3=3^2-2.3.\sqrt{3}+\left(\sqrt{3}\right)^2\)
=\(\left(3-\sqrt{3}\right)^2\)