Stuck on binomial expressions x.X

So I'm currently doing questions on binomial expressions, and I'm not sure as to how to do it after this >.> Any guidance? Thank you :]

This is the question: If , find the value of .

So this was what I tried to do:

I thought that it meant triple (we are currently doing expressions related to ^^)

So this was what I did:

And then I simply substituted as given in the question:

And multiplied, and got the answer:

But I'm pretty sure that what I have done is completely wrong.. any help?

Re: Stuck on binomial expressions x.X

Quote:

Originally Posted by

**Lexadis** This is the question: If

, find the value of

.

Re: Stuck on binomial expressions x.X

Quote:

Originally Posted by

**Plato**

Oh I didn't think of it that way ;D

But then again, I'm confused as to how to proceed after that.

= ?

Re: Stuck on binomial expressions x.X

Lexadis

it seems to me that you do not follow at all the instructions of Plato...

JUst substitute ...x^3-1/x^3=(8/3)^3+3(8/3) finally you will get 728/27 i.e 26.9629

Re: Stuck on binomial expressions x.X

Re: Stuck on binomial expressions x.X

Quote:

Originally Posted by

**Lexadis**

You missed a sign:

Re: Stuck on binomial expressions x.X

Quote:

Originally Posted by

**Plato** You missed a sign:

I'm sorry but I just don't understand how a + comes in between.. any explanation?

Re: Stuck on binomial expressions x.X

Quote:

Originally Posted by

**Lexadis** I'm sorry but I just don't understand how a + comes in between.. any explanation?

You have

that gives

Now solve for .

Re: Stuck on binomial expressions x.X