$\displaystyle \mathop {\lim }\limits_{x \to {0^ + }} {{x + 2\sqrt x } \over {x - \sqrt x }}$

  $\displaystyle \mathop {\lim }\limits_{x \to {2^ - }} {{4 - {x^2}} \over {\sqrt {2 - x} }}$

$\displaystyle \mathop {\lim }\limits_{x \to {{\left( { - 1} \right)}^ + }} {{{x^2} + 3x + 2} \over {\sqrt {{x^5} + {x^4}} }}$

 $\displaystyle \mathop {\lim }\limits_{x \to {3^ - }} {{\sqrt {{x^2} - 7x + 12} } \over {\sqrt {9 - {x^2}} }}$