Chapter 11 - 11.5 - The Binomial Theorem - 11.5 Exercises - Page 813: 39

$120x^7y^3$

According to the Binomial Theorem we can obtain the $r+1$th term of the expansion of the binomial $(x+y)^n$ by the formula $_nC_rx^{n-r}y^r$. Hence here it is: (by plugging in $n=10,r=3$ and $x,y$): $_{10}C_3(x)^{10-3}y^3=120x^7y^3$