SOLUTION: Hello - need help PLEASE!! I need to determine if the given x-value is a zero of the function - show work f(x)=x^3+5x^2+2x-8 Is x= -2 a root -- don't undrstand at all thanks

Algebra ->  Polynomials-and-rational-expressions -> SOLUTION: Hello - need help PLEASE!! I need to determine if the given x-value is a zero of the function - show work f(x)=x^3+5x^2+2x-8 Is x= -2 a root -- don't undrstand at all thanks       Log On


   

Question 94022: Hello - need help PLEASE!!
I need to determine if the given x-value is a zero of the function - show work
f(x)=x^3+5x^2+2x-8
Is x= -2 a root -- don't undrstand at all
thanks
llo
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
f(x)=x^3+5x^2+2x-8
Is x= -2 a root
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If -2 is a zero of the function f(-2) will be zero.
Try it:
f(-2) = (-2)^3 + 5(-2)^2 + 3(-2) -8
f(-2) = -8 +5*4 -6 -8
f(-2) = -22 +20
f(-2) -2
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Since the result is not zero -2 is not a zero.
Cheers
Stan H.