$\frac{x+13}{4}+4$

$\left(x-a\right)^2-2\left(x-a\right)-15$

$\left(x^{2n}-y^{3n}\right)\left(x^{2a}+y^{3a}\right)$

$\lim_{x\to1}\left(\frac{30\left(x-1\right)^{\frac{1}{3}}}{x^3-1}\right)$

$-\left(+9\right)-\left(-3\right)+2$

$\left(1+xe^{xy}\right)\frac{dy}{dx}+1+ye^{xy}=0$

$\frac{x^2}{9y^2}+\frac{5}{6xyz}$