$-\frac{4x-6x}{2}$

$4\left(-5\right)\left(-4\right)$

$\left[cos\left(-x\right)\:-1\right]\left[1+cos\left(x\right)\right]=-sin^2x$

$16m^4n^2-24m^2n^2+9n^4$

$\sqrt{3}csc^2x+cscx=0$

$x\left(8+9x\right)$

$\tan\left(\frac{x}{2}+\frac{\pi}{4}\right)=sec\left(x\right)+tan\left(x\right)$