$x^2+5<0$

$\left(23-15+16\right)-\left(31+12-28\right)+\left(17-15\right)-\left(8-2+1\right)$

$\left(4+6xy\right)=5x-12y$

$\lim_{x\to10}\frac{x-10}{\sqrt{6+x\:\:}-4}$

$\sin x\left(\csc x-\sec x\right)=1-\tan$

$\frac{\cos\left(x\right)}{1-\sin\left(x\right)}=\frac{1+sinx}{cosx}$

$-2.2+3$