$\left|2\left(-7\right)-1\right|-\left|5-\left(-7\right)\right|+\left(-7\right)^2$

$\lim_{x\to\pi}\:\frac{\left(x-\pi\right)}{tan\left(x\right)}$

$\frac{y^2}{x^3}=0$

$csc\:\left(a\right)+cot\left(a\right)=\:\frac{sen\left(a\right)}{1-cos\:\left(a\right)}$

$1-\left(-14\right)$

$\int\left(x+2\right)\cdot ln\left(x\right)dx$

$\left(4+3-8\right)+12\left(12\right)$