$\left(2x-3y\right)\left(4x^2+6xy+9y^2\right)\left(8x^3-27y^3\right)$

$\frac{2x^2-2x^3+8x^2-5x+6}{\left(x-1\right)\left(x^2+2\right)^2}$

$\frac{2x^2+3}{x^2+1}$

$\int6x^2e^{-3x}dx$

$4+9-9-2+5-2-5+4$

$8+\left[9-\left\{6-\left(5-4\right)\right\}\right]+14-\left\{11-\left[7-\left(3-2\right)\right]\right\}$

$-98+46+72-61-81$