Hi MHF

Before I continue I would like to ask you guys for some help.

I want to know where/how can I practice hard Algebra questions?

How did you guys get so good? Any tips? Any book? Any website?

Thanks

Now, for the question

We have to find the value of $\displaystyle x^4+y^4+z^4$ when $\displaystyle x$ ,$\displaystyle y $ and $\displaystyle z$ are real numbers.

Following three equalities:

$\displaystyle x+y+z=3$

$\displaystyle x^2+y^2+z^2=9$

$\displaystyle xyz$$\displaystyle =-2$

First, from the first two equations we have (this is actually in the question)

$\displaystyle xy+yz+xz=A$

Next using

$\displaystyle (x^2+y^2+z^2)^2=x^4+y^4+z^4+B[(xy)^2+(yz)^2+(zx)^2]$

We have

$\displaystyle (x^4)+(y^4)+(z^4)=C$

I know NOTHING about this question. It asks to find $\displaystyle A,B$ and $\displaystyle C$ ;all these equations are given.

So,

any tips?

Last time I asked something here I got a really good response and actually got to know that I had missed somethings in school.

Am I missing out something?

Thanks a lot!!!