$\lim_{x\to infinity}\left(\frac{ln\left(x\right)}{x^{-1}}\right)$

$5\int sin\left(ln\left(9x\right)\right)dx$

$y^2\cdot dx-x\cdot y\cdot dy=x^2\cdot y\cdot dy$

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

$5a^{7}b^{2}-3a^{4}b^{2}+10ax$

$5n\:+\:2n\:-\:7n$

$\ln\left(3x^3-4\right)\left(9x^2-4\right)$