$x^2+3x+5x+15$

$\left(13^2\right)^6\cdot13^{-11}$

$\lim_{t\to\infty}\:\left[tln\left(\frac{3}{t}\right)\right]$

$\frac{\left(2x+xy^2\right)}{\left(4y+yx^2\right)}$

$\frac{x^{5\left(4\right)+3}-y^{5\left(4\right)+30}}{x^{\left(4\right)-1}-y^{\left(4\right)+2}}$

$\left(\frac{3}{4}\right)^3\:x\:\left(\frac{1}{2}\right)^3$

$\frac{\:dr}{\:ds}=0.75r$