What are the possible numbers of positive, negative, and complex zeros of f(x) = 2x3 - 3x2 + 4x + 5 ?
Choose one answer.
a. pos:3 or 0 neg:1 com:2 or 0
b. pos:3 or 1 neg:1 com:3 or 1
c. pos:2 or 0 neg:1 com:2 or 0
d. pos:1 or 0 neg:2 com:2 or 0

Question

What are the possible numbers of positive, negative, and complex zeros of f(x) = 2x3 - 3x2 + 4x + 5 ?
Choose one answer.
	a. pos:3 or 0 neg:1 com:2 or 0 	
	b. pos:3 or 1 neg:1 com:3 or 1 	
	c. pos:2 or 0 neg:1 com:2 or 0 	
	d. pos:1 or 0 neg:2 com:2 or 0

anonymous · Answer

Plug in the answers to see if you find $f(x)=0$.

anonymous · Answer

I think its b is that right?

anonymous · Answer

never mind i got it

mertsj · Answer

There are 2 sign changes so the possible number of positive roots is 2 or 0

mertsj · Answer

So what do you say it is?

anonymous · Answer

Are you sure that formula is correct? WolframAlpha gives irrational roots: http://www.wolframalpha.com/input/?i=roots+of+2x%5E3+-+3x%5E2+%2B+4x+%2B+5

mertsj · Answer

So how many positive ones did Wolf find?

anonymous · Answer

I got it its c

anonymous · Answer

OH I'm sorry...i see it says NUMBER of pos/neg roots.... thought those were the roots themselves.

mertsj · Answer

Yes.  C is correct.