Answer
$13,440x^{4}y^{6}$
Work Step by Step
(See p. 884)
The term that contains $a^{r}$
in the expansion of $(a+b)^{n}$ is$ \left(\begin{array}{l}
n\\
r
\end{array}\right)a^{r}b^{n-r}$.
---------------
$\left(\begin{array}{l}
n\\
r
\end{array}\right)a^{r}b^{n-r}=\left(\begin{array}{l}
10\\
4
\end{array}\right)x^{4}(2y)^{6}$
$=\displaystyle \frac{10\cdot 9\cdot 8\cdot 7}{1\cdot 2\cdot 3\cdot 4}\cdot 2^{6}x^{4}y^{6}$
$=13,440x^{4}y^{6}$
