The general term of the binomial expansion of (2x+5y)^10 is given by:
T(r+1) = (10Cr)(2x)^(10-r)(5y)^r
where r is the term number and Cr is the binomial coefficient.
To find the 5th term, we can set r = 4:
T(5) = (10C4)(2x)^(10-4)(5y)^4
T(5) = (210)(2x)^6(5y)^4
T(5) = 210(64x^6)(625y^4)
T(5) = 8400000x^6y^4
Therefore, the 5th term of the expansion is 8400000x^6y^4.