Answer
$\frac{5}{4}xy^4$
Work Step by Step
Use the formula for binomial expansion, we have:
$(4x-\frac{1}{2}y)^5=(4x)^5+5(4x)^4(-\frac{1}{2}y)+10(4x)^3(-\frac{1}{2}y)^2+10(4x)^2(-\frac{1}{2}y)^3+5(4x)(-\frac{1}{2}y)^4+(-\frac{1}{2}y)^5$
and the fifth term is $5(4x)(-\frac{1}{2}y)^4=\frac{5}{4}xy^4$
