OCR FP1 Roots of Polynomial Question

Replace all occurrences of x with u+2. So x^3 becomes (u+2)^3 and so on, then expand out.

Unless I've expanded incorrectly, I keep ending up with u^3 -5 = 0

No idea what to even do with that.

Sorry, still really confused!

You really can't find a solution for $x^3 = 5$ ?

No, I meant that because the questions asks for the exact real root of the equation, and the solutions for x^3 -5 = 0 are all real but not exact, it's not giving me the correct answer, so I must be doing something fundamentally wrong.

I can find the solutions to x^3 = 5 though!

Unless I've expanded incorrectly, I keep ending up with X^3 -5 = 0

No idea what to even do with that.

Sorry, still really confused!

I don't think you know what exact means.

$u=\sqrt[3] 5$ is exact. Stop changing u (incorrectly) to x!

Ooops, sorry! I entered it into my calculator, and it gave me a decimal answer, therefore I thought it couldn't be exact. Bit stupid really.

So, my root answer would be $\sqrt[3] 5 + 2$ ?

Yes.

Do you get u^3-5=0? If so, find u's real root, then substitute back that u=x-2