${r^{th}}$ term in the expansion of ${(a + 2x)^n}$ is
${r^{th}}$ term in the expansion of ${(a + 2x)^n}$ is
- A
$\frac{{n(n + 1)....(n - r + 1)}}{{r!}}{a^{n - r + 1}}{(2x)^r}$
- B
$\frac{{n(n - 1)....(n - r + 2)}}{{(r - 1)\,!}}{a^{n - r + 1}}{(2x)^{r - 1}}$
- C
$\frac{{n(n + 1)....(n - r)}}{{(r + 1)!}}{a^{n - r}}{(x)^r}$
- D
None of these
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