I will fan and medal!!!! Please help!!
Three roots of the polynomial equation x^4 - 4x^3 - 2x^2 + 12x + 9 = 0 are 3, -1 and -1. Explain why the fourth root must be a real number. Find the fourth root.

Question

I will fan and medal!!!! Please help!!
Three roots of the polynomial equation x^4 - 4x^3 - 2x^2 + 12x + 9 = 0 are 3, -1 and -1. Explain why the fourth root must be a real number. Find the fourth root.

anonymous · Answer

Use Descartes rule of signs to prove that the fourth root must be a real number

anonymous · Answer

Not sure if this will help but I got this :)

www.mathportal.org/calculators/polynomials-solvers/polynomial-factoring-calculator.php?formId=0&val1=x^4+-+4x^3+-+2x^2+plus+12x+plus+9

anonymous · Answer

She has to explain how she got it, so she needs to be able to do it.

anonymous · Answer

@swagmaster47 i hae never even heard of descartes ru;es of signs

anonymous · Answer

@swagmaster47 There's an explanation in the link provided :)

anonymous · Answer

okay thans @goku-kai