Question 117938
factor 12x^3-3xy^2

and one other   8m^4n-16mn^4

1) Factor out 3

3(4x^3 -xy^2)

Now you can see that an x is found in both terms, so factor it out.
3x(x^2-y^2)

Now you have 3x times the difference of two squares, so rewrite the expression inside the parentheses.
3x(x-y)(x+y)

2) Factor out 8
8(m^4n-2mn^4)

Now you can see that an n is found in both terms, so factor it out.

8n(m^4-2mn^3)

Lastly, factor out the m.
8mn(m^3-2n^3)

Hope that helps.

Greetings,
misscrt