rút gọn:
\(a,\frac{\sqrt{4mn^2}}{\sqrt{20m}}\left(m>0,n>0\right)\)
\(b,\frac{\sqrt{16a^4b^6}}{\sqrt{12a^6b^6}}\left(a< 0,b\ne0\right)\)
\(c,\frac{y-\sqrt{xy}}{x-\sqrt{xy}}\)với\(xy>0,y\ne1\)
\(d,\frac{x\sqrt{x}-y\sqrt{y}}{\sqrt{x}-\sqrt{y}}\)với \(x>0,y>0,y\ne1\)
\(e,\sqrt{\frac{x-2\sqrt{x}+1}{x+2\sqrt{x}+1}}\)với \(x>0\)
a) \(\frac{\sqrt{4mn^2}}{\sqrt{20m}}=\sqrt{\frac{4mn^2}{20m}}=\sqrt{\frac{n^2}{5}}=\frac{n}{\sqrt{5}}\)
b) \(\frac{\sqrt{16a^4b^6}}{\sqrt{12a^6b^6}}=\sqrt{\frac{16a^4b^6}{12a^6b^6}}=\sqrt{\frac{4}{3a^2}}=\frac{2}{\sqrt{3}.\left|a\right|}=-\frac{2}{a\sqrt{3}}\)
d) \(\frac{x\sqrt{x}-y\sqrt{y}}{\sqrt{x}-\sqrt{y}}=\frac{\left(\sqrt{x}-\sqrt{y}\right)\left(x+\sqrt{xy}+y\right)}{\sqrt{x}-\sqrt{y}}=x+\sqrt{xy}+y\)
e) \(\sqrt{\frac{x-2\sqrt{x}+1}{x+2\sqrt{x}+1}}=\sqrt{\frac{\left(\sqrt{x}-1\right)^2}{\left(\sqrt{x}+1\right)^2}}=\frac{\left|\sqrt{x}-1\right|}{\sqrt{x}+1}\)