$6-\left(-2\right)+5-20$

$\frac{3}{4}\:=\:\frac{1}{4}\:x$

$4\left(3\:+\:\frac{1}{4}c\:-\:\frac{1}{2}d\right)\:$

$\left(\frac{1}{2}a^2b^2-4b^5\right)\left(\frac{1}{2}a^2b^2+4b^5\right)$

$\left(x-2\right)^2=x\left(x-2\right)$

$27x^3-64$

$\lim_{x\to-2}\left(\frac{\left(5x+10\right)}{\left(3-sqrt\left(x+11\right)\right)}\right)$