$\lim_{x\to-\infty}\left(\frac{4x^2+e^x}{2x^2-5x+1}\right)$

$-5x^2y+3yx-5x;\:x=-2;\:y=1$

$\lim_{x\to0}\left(\frac{x-4}{x-\sqrt[2]{8-x}}\right)$

$\tan x+4\cot\tan x=5$

$x^2-18=25$

$\frac{x^4-13x^2-25x-12}{\left(x^2-4\right)}$

$\int\frac{4u^9}{\left(u^5+3\right)^3}du$