*From*: David Ritchie <ritchierd@xxxxxxxxxxxxx>*To*: lit-ideas@xxxxxxxxxxxxx*Date*: Fri, 23 Jun 2006 14:10:25 -0700

`Hi Erin,
my dad asked me if I knew how to do this, and coincidentally, we just
went over this this year in math class.
How you solve the problem is you first multiply out (x+y)^4, which
gives you, if you don't simplify it completely,
(x^2+2xy+y^2)(x^2+2xy+y^2). This is the same as the first equation,
only multiplied by itself, so to get the answer, you need to multiply
the 9 by itself, which gives you 81. I hope this helps.
Julia Ritche`

On Jun 23, 2006, at 12:35 PM, Erin Holder wrote:

OK, who can explain to me how to solve this:

If x^2+2xy+y^2 = 9 then (x+y)^4 = ?

I know the answer is "81", I just don't know how to get it. It's starting to

frustrate me. I haven't done this stuff in almost ten years, and I can't for

the life of me remember how to go about it (although I seem to be getting the

hang of some of the other ones...?)

Erin TO

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**Follow-Ups**:**[lit-ideas] Re: Don't Laugh (Math)***From:*Erin Holder

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**[lit-ideas] Don't Laugh (Math)***From:*Erin Holder