$\frac{5^2}{\left(1-3x\right)^2}$

$8x^5y^5-9x^4y^6$

$\int\frac{-4x+6}{\left(2x-1\right)\left(x+3\right)}dx$

$\left(5+i\right)\:x\left(1-3\:x\:i\right)$

$\frac{d^6}{dx^6}\left(sen\left(x\right)\right)$

$\frac{4}{x-1}+x=7$

$\lim\:_{x\to+0}\left(x^{\left(\ln\:\left(x\right)\right)^2}\right)$