$6xy\:and\:10ax$

$\frac{\left(1+sin\left(\theta\:\right)\right)}{cos\theta\:}=\left(\frac{cos\left(\theta\:\right)}{1-sin\left(\theta\:\right)}\right)$

$f\left(x\right)=\frac{1}{x^4+16}$

$\int\frac{102}{x\left(x^2+20x+51\right)}dx$

$\left(x^2-xy-y^2\right)\left(x^2+y^2+xy\right)$

$x\frac{dy}{dx}+2y=3x^2+2x$

$\left(2a^3+1\right)x\left(2a^3-1\right)$