$\mathop {\lim }\limits_{x \to  - 1} {{2x + 1} \over {{x^2} - 3x + 4}}$          

$\mathop {\lim }\limits_{x \to 2} \sqrt {{{{x^3} + 2x + 3} \over {{x^2} + 5}}}$  

$\mathop {\lim }\limits_{x \to  - 2} {{{x^3} - {x^2} - x + 10} \over {{x^2} + 3x + 2}}$    

$\mathop {\lim }\limits_{x \to  - 3} \left| {{{9 - {x^2}} \over {2{x^2} + 7x + 3}}} \right|.$