Rút gọn
\(2x-\sqrt{4x^2+4x+1}\)với x bé hơn -1/2
\(3x+2-\sqrt{9x^2-12x+4}\)
\(\sqrt{9a}-\sqrt{16a}+\sqrt{49a}vớia\ge0\)
\(\sqrt{160a}+2\sqrt{40a}-3\sqrt{90a}vớia\ge0\)
\(\frac{3}{a^2-b^2}\sqrt{\frac{2a^2-4ab+2b^2}{9}}\)
\(\left(1-\frac{x-3\sqrt{x}}{x-9}\right)\div\frac{\sqrt{a}+1}{a}\)