Answer
$56\cdot x^6\cdot y^{15}$
Work Step by Step
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 $n=8,r=5$ and $x^2,y^3$: $_{8}C_5(x^2)^{8-5}(y^3)^5=56\cdot x^6\cdot y^{15}$
