1) Rút gọn
a) A=\(\dfrac{x+\sqrt{xy}}{y+\sqrt{xy}}\)
b) B= \(\sqrt{\dfrac{\left(a-b\right)^3.b^3}{c}}\) .\(\sqrt{\dfrac{bc^3}{\left(a-b\right)}}\) ( với a-b>0, c<0)
c) C=(\(\sqrt{3+2\sqrt{2}}\) - \(\sqrt{3-2\sqrt{2}}\) ).(\(\sqrt{3-2\sqrt{2}}\) +\(\sqrt{3+2\sqrt{2}}\)
2) Giải phuong trình
a) \(\sqrt{x^2-4}\) -\(\sqrt{x-2}\) =0
b)\(\sqrt{3x^2+12x+16}\) +\(\sqrt{y^2-4y+13}\) =5