2a^2b^3(4a^2+3ab^2-ab)=?
is what I presume you actually meant.
Pull out the common factors of (4a^2+3ab^2-ab) and you will get
a(4a+3b^2 -b)
Substitute this back into the original equation and you get
2a^2b^3[a(4a+3b^2-b)] =
2a^3b^3(4a+3b^2-b) =
2a^3b^3(4a-b+3b^2)
