$-24x^5y^5z^7-20x^2y^3z^3$

$0.5\:\left(2x+3\right)$

$\int7x^2cos\left(9x\right)dx$

$\frac{d}{dx}\frac{1}{x}ln\left(18x+cosx\right)$

$-4\left(9+6\right)$

$\frac{1+cos\left(x\right)+sen\left(x\right)}{1+cos\left(x\right)-sen\left(x\right)}=1$

$\frac{dy}{dx}=\frac{x+4}{9\left(x+3\right)^2}$