$\lim\:_{x\to\:0}\left(\frac{\sqrt{x+a+b}-\sqrt{a+b}}{x}\right)$

$x^2\:-8x\:-5\:=\:0\:$

$\frac{\sin\left(x\right)+\sin\left(3x\right)}{\cos\left(x\right)-\cos\left(3x\right)}=\cot\left(x\right)$

$6a^3d+9a^2b^2-3a^2b$

$\lim_{x\to\infty}\left(\frac{-4ln\left(x^5\right)}{\sqrt[3]{5x+19}}\right)$

$\int\frac{7x-4}{x^3-2x^2-15x}dx$

$-3x-3y$