$\left(\frac{5x^3}{3}-x^2+\frac{2x}{5}-7\right).\left(\frac{5x^2}{4}-3x\right)$

$3\:-18\:-12\:+\:5\:+\:3$

$\frac{d^2}{dx^2}e^{2x}$

$\lim_{x\to-1}\left(\frac{2x^4+x^3+7x+6}{x+1}\right)$

$x^2-10x=-5$

$\left(6\frac{1}{3}-2\frac{1}{4}\right)\left(3-2^2-\frac{1}{2}^3\right)$

$3m^2n-7-6m^2n-11$