Need a little help with biquadratic equations

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SUMMARY

The discussion focuses on proving that for the biquadratic equation \(x^4 + px^2 + q = 0\), the sum of all solutions equals zero and the product of the solutions equals \(q\). The equation can be transformed into a quadratic form by substituting \(u = x^2\), resulting in \(u^2 + pu + q = 0\). By applying the quadratic formula, two values of \(u\) can be derived, which can then be substituted back to find four values of \(x\). The relationship between the coefficients and the roots of the polynomial is emphasized as a key concept in this proof.

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Homework Statement



Ok, so here's the problem:
Prove, that biquadratic equation's x4+px2+q=0 sum of all solutions is equal to zero, and product is equal to q.

Homework Equations





The Attempt at a Solution


I don't really know how to solve it so I'd be very grateful if someone could help me. Thank you
 
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This equation is quadratic in form, which you can see by letting u = x2. This makes the new equation u2 +pu + q = 0.
Solve that equation for u by using the quadratic formula, getting two values of u.
Replace u by x2, getting four values of x.
 
While that equation is quadratic in form, for the purpose of the question think of it as x4+ 0*x3+ px2 +0*x+q=0. Do you know any general ways to relate the coefficients of a polynomial with the roots? If you're having trouble try multiplying out (x-a)(x-b)(x-c)(x-d)=0. That will become a polynomial with roots equal to a,b,c, and d.
 

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