$8a^2b-ab$

$-\frac{1}{3}n=3$

$2\left(3\right)\left(2\right)-5\left(3\right)^2\left(2\right)$

$tan\left(2x\right)=\frac{2}{5}$

$\frac{r^{-7}}{r^{-4}}$

$\frac{\left(\sin\left(x\right)-\sin\left(3x\right)\right)}{\left(\cos\left(x\right)-\cos\left(3x\right)\right)}$

$\int\left(\frac{sin\left(x\right)cos\left(x\right)}{sin^4\left(x\right)+sin^2\left(x\right)}\right)dx$