$2x-y;x=1,y=2$

$\left(3x+8y\right)\left(2x+4y\right)$

$\left(\frac{2}{3}x^3\:+\frac{5}{2}y^2\right)\:\left(\frac{2}{3}x^3-\:\frac{5}{2}y^2\right)$

$\int e^{1-x}dx$

$\int_1^x\left(t^3\right)dx$

$-\frac{3pq}{r}+\frac{5p^4p^{-3}r^{-1}}{q}-\frac{2r^{-1}p^{-2}}{p^{-3}q^{-1}}$

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