$12r^2+36rs+27s^2$

$\lim_{x\to0}\left(\frac{2-2\cos\left(x\right)}{x^2}\right)$

$\left(i+5j-k^3\right)^2$

$\lim_{x\to0}\left(\frac{1-\cos\left(x\right)}{\left(e^{2x}\right)-1}\right)$

$5\left(1+\frac{2y}{n}\right)^4$

$\int\frac{4x+1}{\left(x-1\right)\left(x+3\right)}dx$

$\left(x+2\right)\left(x+3\right)\left(5x+3y\right)^2$