Find the exact value of the radical expression in simplest form. Squareroot(16y^3) - Squareroot(y3)Please explain how! :(

Question

luigi0210 · Answer

$$\sqrt{16y^3}-\sqrt{y^3}$$
This?

anonymous · Answer

oh wait yes! sorry i wrote the question wrong xD

luigi0210 · Answer

Well just break it down to square roots that you know of:
$$\sqrt{16y^2*y}-\sqrt{y^2*y}$$

anonymous · Answer

$$4\sqrt{y^2*y} - \sqrt{y^2*y} $$ I'm sorry I'm kind of slow, I'm new here so xD Is this how you do it?

anonymous · Answer

The answer is $$3y^2 \sqrt{y}$$ right?

luigi0210 · Answer

How did the 4 turn into a 3? :P

anonymous · Answer

Oh oops, brain fart. Like i assume the answer is four, but in the multiple choices said it doesn't have the answer '4' So I'm a bit confused hahaha.. I'm probably wrong with the 4

anonymous · Answer

Is it $$4y \sqrt{y} $$ >_<?

luigi0210 · Answer

Sorry about that.. tech difficulties..
|dw:1376609427073:dw|