Question 825417: List the possible rational zeros the function f(x) =  ? Describe and use one method (other than substitution) to determine if x = 6 is a zero of f(x). Then find all the real zeros of the function.
Answer by stanbon(75887)   (Show Source):
You can put this solution on YOUR website! List the possible rational zeros the function
f(x) = 3x^3 - 21x + 18
Form: x = p/q
p = +-1,+-2,+-3,+-6,+-9,+-18
q = +-1,+-3
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p/q = +-1,+-2,+-3 etc,etc
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Describe and use one method (other than substitution) to determine if x = 6 is a zero of f(x).
Using synthetic division::
6)....3....0....-21....18
......3...18....33...|..216
Since the remainder is not zero, x = 6 is not a zero of f(x).
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Then find all the real zeros of the function.
Using synthetic division:: x = 1,2,-3
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Cheers,
Stan H.
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