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# Roots of Polynomial Equations Help watch

1. I have been having some trouble with a question in FP1, any help would be greatly appreciated and you would be a friend for life

x^2-5x+7=0 has roots alpha and beta.

Then asked to find an equation with roots alpha^2 and beta^2...no problem, x^2-11x+49=0

It then says:
Show how the equation whose roots are alpha^2 and beta^2 may alternatively be obtained from the orginal quadratic equation by means of the substitution y=x^2. This is the part I can't bloody do!

Thanks for any help.

Chris.
2. Make the substitution, the 5x term becomes 5 sqrt(y). Isolate this term over to one side and square both sides.
3. Thanks very much, made it sound easy...which it was with your help ha.

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Updated: January 18, 2010
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