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1. X^4-8X^2+8 how do i solve this with a caculator btw i havnt got the grey one. or can i use the quadratin formula??

2. Yeah if you let
then you get

And you use the quadratic formula to find .

When you've found it, square root it to find , because and make sure to take both the positive and negative square root. i.e.
3. (Original post by maxfire)
i.e.
I should point out that this isn't actually correct. unambiguously (only +2, not -2), however the solutions to the equation are given by (the square root always refers to the positive root).

Other than that, what maxfire said is right. That is, you should take the positive and negative square roots.
4. (Original post by maxfire)

Yeah if you let
then you get

And you use the quadratic formula to find .

When you've found it, square root it to find , because and make sure to take both the positive and negative square root. i.e.
thank youuu

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Updated: January 18, 2010
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