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Could I get help on one more?

 

What are the zeros of the polynomial function?

f(x)=x4+2x3−16x2−2x+15

 

Options

 

−5

−1

0

1

3

5

 

Please and thank you! 0^>

 Nov 8, 2018
 #1
avatar+5233 
+1

\(x^4+2x^3 -16x^2 -2x+15 =\\ (x^4-16x^2+15) + (2x^3-2x)= \\ (x^2-15)(x^2-1) + 2x(x^2-1) = \\ (x^2+2x-15)(x^2-1) = \\ (x+5)(x-3)(x-1)(x+1) \\ \\ \text{zeros are read off as }\\ x=-5,~3,~1,~-1\)

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 Nov 8, 2018

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