$f\left(x\right)=x^2-5x^2-x+5$

$\lim_{x\to1}\left(\frac{x^3-3x+2}{1-x+inx}\right)$

$\lim_{x\to\infty}\left(6+\frac{1}{x^2}-\frac{1}{x^3}\right)\:$

$a+2=6$

$\frac{x}{\sqrt{-1-4x^2-8x}}$

$\lim_{x\to-2}\left(\frac{\frac{1}{x\:+\:2}-\:\frac{1}{2}}{x\:}\right)$

$y^2-2yx+x^2$