$log_{0.84}x$

$\frac{2}{a^2}-\frac{3}{ab}+\frac{4}{b^2}$

$20+90+bc$

$\int\frac{2x}{\left(x^2-5x-36\right)}dx$

$\frac{4x^4+4x^4}{2x^2+2x^2}$

$f\left(x\right)\:=\:\:2x\left(x\:+\:1\right)\left(x\:-\:4\right)^2\left(\:2x\:-\:3\right)$

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