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

$\left(16p+20q\right).\left(16p-20q\right)$

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

$-\left(13+\left(-4\right)\right)-\left(-12\right)-2+4\left(-1\right)$

$y''+2y'+10y=0,\:y\left(0\right)=-2\:and\:y'\left(0\right)=0$

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

$\sqrt[7]{-2.187}$