`~rai~`
\(a)\dfrac{3}{5}\sqrt{50}-\dfrac{2}{3}\sqrt{162}+\dfrac{1}{2}\sqrt{32}\\=\dfrac{3}{5}\sqrt{25.2}-\dfrac{2}{3}\sqrt{81.2}+\dfrac{1}{2}\sqrt{16.2}\\=\dfrac{3}{5}\sqrt{25}.\sqrt{2}-\dfrac{2}{3}\sqrt{81}.\sqrt{2}+\dfrac{1}{2}.\sqrt{16}.\sqrt{2}\\=\dfrac{3}{5}.5\sqrt{2}-\dfrac{2}{3}.9\sqrt{2}+\dfrac{1}{2}.4\sqrt{2}\\=3\sqrt{2}-6\sqrt{2}+2\sqrt{2}\\=-\sqrt{2}.\\b)2x-3-\sqrt{9-12x+4x^2}\quad(x<\dfrac{3}{2})\\=2x-3-\sqrt{(2x-3)^2}\\=2x-3-|2x-3|\\=2x-3-(3-2x)\quad\text{(vì x<}\dfrac{3}{2})\\=2x-3-3+2x\\=4x-6.\\c)\sqrt{x^2-4x+4}-\sqrt{x^2+4x+4}\quad(-2\le x\le 2)\\=\sqrt{(x-2)^2}-\sqrt{(x+2)^2}\\=|x-2|-|x+2|\\=2-x-(x+2)\quad\text{(vì -2}\le x\le2)\\=2-x-x-2\\=-2x.\)
