SOLUTION: If P(x) = x^3 + 4x^2 - 8x - 15 Use the remainder theorem to find P(-5).

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Question 370593: If P(x) = x^3 + 4x^2 - 8x - 15
Use the remainder theorem to find P(-5).
Found 2 solutions by stanbon, robertb:
Answer by stanbon(75887) About Me  (Show Source):
You can put this solution on YOUR website!
If P(x) = x^3 + 4x^2 - 8x - 15
Use the remainder theorem to find P(-5).
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Using synthetic division:
-5)....1....4....-8....-15
........1....-1....-3....|..0
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P(-5) = 0
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Cheers,
Stan H.
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Answer by robertb(5830) About Me  (Show Source):
You can put this solution on YOUR website!
Direct substitution gives P%28-5%29+=+%28-5%29%5E3+%2B+4%2A%28-5%29%5E2+-+8%28-5%29+-+15+=+0. Thus the remainder after dividing x%5E3+%2B+4x%5E2+-+8x+-+15+by x+5 is 0, meaning x+5 is a divisor or factor of x%5E3+%2B+4x%5E2+-+8x+-+15+.