$\left(x^7\right)^{-2}$

$\left(b-9\right)\left(b+4\right)$

$tan^2x-4secx+5$

$16x^2+36y^2-256x+448=0$

$4x^2-8x+1=0$

$\left(\tan\left(x\right)\cdot\csc\left(x\right)+\tan\left(x\right)\right)\cdot\cos\left(x\right)$

$\left(x-2\right)y'-y=\left(x-2\right)^3;\:y\left(0\right)=4$