Question

What are the possible number of positive, negative, and complex zeros of f(x) = –2x^3 + 5x^2 – 6x + 4 ?

A. Positive: 3 or 1; Negative: 1; Complex: 2 or 0

B. Positive: 1; Negative: 2 or 0; Complex 2 or 0

C. Positive: 2 or 0; Negative: 1; Complex: 2 or 0

D.Positive: 3 or 1; Negative: 0; Complex: 2 or 0
think it's B

Answer 1

two complex roots, no positive or negative zeros

Answer 2

thats not a answer choice

Answer 3

Complex roots always come in pairs. So if (a+bi) is a root, so is (a-bi). This is because when you rewrite the polynomial to include (x-(a+bi))*(x-(a-bi)), it is expands to become x^2 - 2ax + (a^2-b^2), and those pesky i's go away!

As it turns out, this is the ONLY way the i's go away, and because there are NO i's in your original equation, then the imaginary roots MUST occur in pairs.

So knowing this, what possible number of complex roots could there be?

Answer 4

I think uve asked there is some problem with ur ques

Answer 5

It's not B

Answer 6

D?

Answer 7

you got it