document.write( "Question 151042: use descartes rule of signs to determine the possible number of positive and negative zeros for the function P(x)= -3x^5 - 7x^3 - 4x-5 \n" ); document.write( "

Algebra.Com's Answer #110971 by Fombitz(32388) $\"\"$ $\"About$

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To use Descartes rules of signs, look at P(x) and P(-x)
\n" ); document.write( " $\"P%28x%29=-3x%5E5-7x%5E3-4x-5\"$
\n" ); document.write( "Since there are no sign changes in the coefficients from + to - or vice versa, then there are no positive roots.
\n" ); document.write( " $\"P%28-x%29=-3%28-x%29%5E5-7%28-x%29%5E3-4%28-x%29-5\"$
\n" ); document.write( " $\"P%28-x%29=3x%5E5%2B7x%5E3%2B4x-5\"$
\n" ); document.write( "There is one sign change from + to -, there is exactly one negative root.
\n" ); document.write( " $\"+graph%28+300%2C+200%2C+-2%2C+2%2C+-10%2C+10%2C+-3x%5E5-7x%5E3-4x-5%29+\"$
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