If it's x²y³ then we know it's the second term of the expansion, that known we can use the combination
C(5, 2) = 5!/(2!.3!) = 10
Then if we had something like
(a + b)^5 our second term would be 10a²b³ but as we can see it's "a²"
And in our case we have 2x as a
So we must do 2² too
2² = 4
10 . 4 = 40
Then our second term of the expansion would be
40x²y³
