Rút gọn biểu thức $A = \sqrt x  - \sqrt {x - \sqrt x  + \dfrac{1}{4}}$ khi $x \ge 0$ ta được:

$P = \sqrt 3  - 1$

$P = \sqrt 3  + 1$

$P = 2\sqrt 3$

$P = \sqrt 3  + 2$

$B > 2$

$B > 1$

$B = 1$

$B < 2$

$Q = \dfrac{{\sqrt x }}{{\sqrt {x + y} }}$                     

$Q = \dfrac{{\sqrt {x + y} }}{{\sqrt {x - y} }}$

$Q = \dfrac{{\sqrt {x - y} }}{{\sqrt {x + y} }}$                     

$Q = \dfrac{{\sqrt y }}{{\sqrt {x + y} }}$

$Q = 2$                             

$Q = \sqrt 2$

$Q = \dfrac{1}{2}$

$Q = \dfrac{{\sqrt 2 }}{2}$

$Q = \dfrac{{\sqrt x }}{{\sqrt {x + y} }}$                     

$Q = \dfrac{{\sqrt {x + y} }}{{\sqrt {x - y} }}$

$Q = \dfrac{{\sqrt {x - y} }}{{\sqrt {x + y} }}$                     

$Q = \dfrac{{\sqrt y }}{{\sqrt {x + y} }}$

$Q = \dfrac{{\sqrt x }}{{\sqrt {x + y} }}$                     

$Q = \dfrac{{\sqrt {x + y} }}{{\sqrt {x - y} }}$

$Q = \dfrac{{\sqrt {x - y} }}{{\sqrt {x + y} }}$                     

$Q = \dfrac{{\sqrt y }}{{\sqrt {x + y} }}$