$\lim_{x\to1}\left(\frac{-3x-y}{x+y}\right)$

$\lim_{t\to\frac{\pi}{4}}\left(1-tanx\right)sec2x$

$\int\left(\frac{arcsec2x}{\sqrt{1-4x^2}}\right)dx$

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

$50xy+20x+20y+8$

$2a^2+3a+2a^2-5$

$\int\frac{\left(4x-1\right)}{\left(x^2+x-2\right)}dx$