$\frac{d}{dx}7\:\sin\left(x^2\right)$

$2\log x-4\log y$

$\frac{d}{du}\left(\frac{\left(u+1\right)\left(u+3\right)}{\left(u^3+1\right)\left(u^2+3\right)}\right)^{\frac{1}{3}}$

$3 - 8 s + 4 s + 9$

$25u^2-90u+81$

$4y^{2}-3y+9y^{4}+7y-5y^{2}$

$2\left(2x-5\right)\left(-3x-1\right)=6\left(-x-3\right)$