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Cardan solved x + y = 10 and xy = 40 and got x = 5 plus root of what?
Aroot(-40) with y = 5 minus the same
Broot(-15) with y = 5 minus the same
Croot(25) with y = 5 minus the same
Droot(15) with y = 5 minus the same
Answer & Solution
Correct answer: B. root(-15) with y = 5 minus the same
Substituting y = 10 - x gives x^2 - 10x + 40 = 0, so x = 5 plus or minus root(-15).
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