$\int\:\:e\:^{-3x}\left(3x^2-x\right)dx$

$2\cdot\left(x^{2}y^{3}-0.4\right)\left(x^{2}y^{3}+2.3\right)$

$\int\frac{3x^2+4}{x^4-4x^2}dx$

$-13-\left(-9\right)$

$-x^2+8x-7$

$\int sin^5\left(5t\right)cos\left(5t\right)dt$

$\left(\left(x^2+y^2\right)-\left(x^2-y^2\right)\right)+\left(\left(x+y\right)-\left(x-y\right)+\left(y-x\right)\right)$