Knowing binomial expansion of $(1+kx)^n$ shortcut for $(a+kx)^n$ If I've calculated the binomial expansion of $(1+kx)^n$ (where $k$ and $n$ are known) up to some term, is there then a shortcut for calculating $(a+kx)^n$?

Example: Given that the binomial expansion of $(1+6x)^{\frac23}$ up to and including the term in $x^2$ is $1+4x-4x^2$, what is the binomial expansion of $(8+6x)^{\frac23}$ (up to and including the term in $x^2$)?

Hint: 
$$(a+kx)^n=\left(a(1+kx/a)\right)^n = a^n(1+kx/a)^n$$
Of course this assumes that all powers exist, which would be the case for natural $n,$ but e.g. not for $n=2/3, a=-2.$
