$x-7>2x-5$

$\frac{1}{2}x^4+3x^3-6x^2+4x$

$\frac{x+3}{x}-\frac{x}{x-2}=-1$

$\left(2\cdot x\cdot y-e^{2y}\right)\cdot dx+\left(x^2-2\cdot x\cdot e^{2y}-y\right)\cdot dy=0$

$\int2x\tan\left(x\right)\sec^2\left(x\right)dx$

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