$\frac{\left(1+2x-x^2\right)}{\left(1-\frac{1}{2}x\right)}$

$\int\frac{x}{x^2-2x+3}dx$

$\lim_{x\to\sqrt{2}}\left(\frac{x^2-\sqrt{2}x+\sqrt{5}x-\sqrt{10}}{x-\sqrt{2}}\right)$

$2x^2-x-12\le9$

$x-7<12$

$\lim_{x\to\infty}\left(\frac{2x^2-5x+7}{x+3}\right)-2x$

$\lim_{x\to\infty}\left(\left(x^{\frac{1}{3x}}\right)\right)$