$\left(+19\right).\left(-8\right)$

$\frac{x^2+1}{x^2-x-2}$

$\frac{tan\left(x\right)+cot\left(x\right)}{tan\left(x\right)}$

$\int\frac{1}{x^2\sqrt{25\:+\:x^2}}dx$

$\frac{2}{3}\sqrt{27}$

$\int\left(1+\frac{1}{x}\right)\cot\left(x+\ln\left(x\right)\right)dx$

$-\:20\:+\:10\:-\:15\:+\:8\:-\:30\:+12$