$\left(-72+-10\right)\left(-78+-33\right)$

$\lim_{x\to0}\left(\frac{e^2-1-x}{x}\right)$

$x^2+6x+13>0$

$5\left(x-1\right)+3x=7\left(x+1\right)$

$\int\:\frac{e^{\theta\:}d\theta\:}{c+ae^{\theta\:}}$

$\left(1+\sin a\right)\left(1-\sin a\right)=\frac{1}{\sec2a}$

$x^2+6x+5<0$