$-\left(-5\right)^3\left(-3\right)^3-\left(-16\right)$

$21=-4+\frac{x}{-2}$

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

$\left\{2m^2-3n^2\right\}\left\{2m^2+3n^2\right\}$

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

$\frac{d^3}{dx^3}4x^6+secx$

$\int e^x-20\left(1+x^2\right)-1dx$