Question

Simplify 2a^2b^3(4a^2+3ab^2-ab)

Answer 1

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)