$2x^2-3x-1$

$6=-y+1$

$\left(5xy^2-4xy^2+xy-5\right)+\left(8xy^2-5xy-12\right)+\left(6x^2y-9xy^2\right)$

$\left(x\:+\:3\right).\left(x\:+\:2\right)\:>\:x.\left(x\:+\:1\right)\:+\:22$

$\lim_{x\to0}\left(\frac{ln\left(3x+e^{2x}\right)}{4x-5}\right)$

$\lim_{x\to\infty}\sqrt{x}\left(\sqrt{x+13}-\sqrt{x+3}\right)$

$\frac{6x^2-7x-5}{2x+6}$