# Multiplying Variables

## Homework Statement

How would I multiply this together? (3$$\sqrt{2x}$$)(3$$\sqrt{2x}$$)

## The Attempt at a Solution

I can't seem to be able to figure out how to multiply them, i keep getting an answer that is too short.

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Dick
Homework Helper
What do you get?? And are those supposed to be cube roots or 3 times a square root?

3 times a square root. Sorry if it’s not clear.

Dick
Homework Helper
That's fine. So what did you get?

HallsofIvy
Homework Helper
Well you should be able to say what $\sqrt{2x}\sqrt{2x}$ is just from the definition of square root! And I'm sure you know what (3)(3) is!

But are you absolutely sure it is $(3\sqrt{2x})(3\sqrt{2x})$? That's seems a peculiar way to write a very simple question. $(\sqrt[3]{2x})(\sqrt[3]{2x})$ is a much more reasonable (and slightly harder) question.

Let me rephrase the question. I want to know how to multiply somthing like
(2-$$\sqrt{x-1}$$)(2-$$\sqrt{x-1}$$), in other words, how to square a side that has variables in a radical.
After i did this out i got
-4$$\sqrt{x-1}$$+x+3

Dick
Homework Helper
Let me rephrase the question. I want to know how to multiply somthing like
(2-$$\sqrt{x-1}$$)(2-$$\sqrt{x-1}$$), in other words, how to square a side that has variables in a radical.
After i did this out i got
-4$$\sqrt{x-1}$$+x+3

And what could be wrong with that?

symbolipoint
Homework Helper
Gold Member
Commutative and associative properties will let you group the like factors together. You see each factor is squared. 3$$\bullet$$3$$\bullet$$$$\sqrt{2x}$$$$\sqrt{2x}$$, and then just one or two more steps if any.

EDIT: While trying to edit this, to fix the LARGE dots representing multiplication, the typesetting formatting tool is gone; those should really be small dots as can be common for showing multiplication operation. I do not have many of these tags memorized for TEX.

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symbolipoint
Homework Helper
(3)(3)$$\sqrt{2}$$$$\sqrt{2}$$$$\sqrt{x}$$$$\sqrt{x}$$