$\lim_{x\to\infty}\left(\frac{20+3x^2}{x^2+6x+9}\right)$

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

$169^2-196n^2$

$\int\left(\frac{\left(5x-2\right)}{x^2-x-6}\right)dx$

$\int_0^6\left(\frac{\sqrt{25+\left(1+x^2\right)^2}}{1+x^2}\right)dx$

$\lim_{x\to\frac{\pi}{2}}\left(sen\left(x\right)\right)^{tan\left(x\right)}$

$-2\cdot3\cdot5$