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I am using Numerical Mathematics and Computing by Cheney and Kincaid 7th edition. My problem is: use Horner's algorithm to evaluate 2x^4 + 9x^2 - 16x + 12 AT -6.

Does 'at -6' mean I am to solve p(-6)?

I've done it using synthetic division and I got p(-6) = 0. It seems like it's not the answer.

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    yes. I just realized I made a simple mistake in my calculation. I got it now. – 2017-01-06

1 Answers 1

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$$2x^4+9x^2-16x+12=12+x(-16+x(9+x(2x)))$$

For $x=-6$, $$12-6(-16-6(9-6(2(-6))))=12-6(-16-6(9+ 72))=12-6(-16-486)=12+3012$$