$\frac{x^3-8}{x^3-27}\cdot\frac{x^2-3x+9}{x^2+2x+4}$

$-3+2-\left(-3+0\right)+1$

$\int\frac{\sec\left(x\right)\cdot\tan\left(x\right)}{\left(1+\sec\left(x\right)\right)}$

$3x+5-6$

$h^3\cdot h^2\cdot h^4$

$\frac{2x-3}{4}+6\le2\frac{4x}{3}$

$\int_0^{\infty}\left(\frac{1}{-z^2+3z-7}\right)dx$