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Evaluate -2x^4 - 3x^2 + 5x - 9 for x = 2.
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anni012

by anni012 at April 01, 2010

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Well, in this case you know that x = 2, so we can work with that to start. First, you set everything equal to zero and plug in 2 for x. 0 = -2(2^4) - 3(2^2) + 5(2) - 9 0 = -2(16) -3(4) + 10 - 9 0 = -32-12+10-9 = -44 + 1 = -43 So, when x = 2, the evaluation to this problem is -43.

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yankeekid

yankeekid April 01, 2010

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While I agree with most of the last post, PLEASE don't "set everything equal to zero".This is an expression...there is no equal sign.Besides, if you look part way down the work, you can find a line where 0 = some stuff = -43.In other words, 0 = -43 (hint: that's false)Lesson learned: Don't just set things equal to zero all willy-nilly.

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McMayer

McMayer April 02, 2010