$-11\:-\:\:23\:+\left[\left(-23\:-56\right)\:-\:\left(27\:-\:65\right)\right]\:-\:\left[-12\:+\:\left(-8\:-17\right)\right]\:$

$\frac{d}{dx}\sqrt{\frac{4-x^2}{4+x^2}}$

$\left(z^2-12\right)\left(z^2-6\right)$

$12x^2-6y^2$

$6x^2-13x-5$

$9+9\sin\left(x\right)=6\cos^2\left(x\right)$

$m^3\sqrt{x^4}$