$-3xz+\frac{8}{3}xz$

$( 6 x y ) ( b c ) ( b x )$

$\frac{dy}{dx}=\frac{15+x}{xy^6}$

$\left(\left(3n-1\right)\cdot\left(n-3\right)\right)$

$cos\left(x+\frac{\pi}{4}\right)=\frac{1}{\sqrt{2}}$

$\frac{x^2+3}{x\left(x^2+x+6\right)}$

$\lim_{x\to0}\left(\frac{4^x-1}{8^x-1}\right)$