SOLUTION: 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

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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
Answer by Fombitz(32388) About Me  (Show Source):
You can put this solution on YOUR website!
To use Descartes rules of signs, look at P(x) and P(-x)
P%28x%29=-3x%5E5-7x%5E3-4x-5
Since there are no sign changes in the coefficients from + to - or vice versa, then there are no positive roots.
P%28-x%29=-3%28-x%29%5E5-7%28-x%29%5E3-4%28-x%29-5
P%28-x%29=3x%5E5%2B7x%5E3%2B4x-5
There is one sign change from + to -, there is exactly one negative root.
+graph%28+300%2C+200%2C+-2%2C+2%2C+-10%2C+10%2C+-3x%5E5-7x%5E3-4x-5%29+