Question

help?
What are the possible numbers of positive real, negative real, and complex zeros of
f(x) = -7x4 - 12x3 + 9x2 - 17x + 3?

Positive Real: 3 or 1
Negative Real: 1
Complex: 2 or 0

Positive Real: 3 or 1
Negative Real: 2 or 0
Complex: 1

Positive Real: 1
Negative Real: 3 or 1
Complex: 2 or 0

Positive Real: 4, 2 or 0
Negative Real: 1
Complex: 0 or 1 or 3

Answer 1

@ganeshie8

Answer 2

@AnswerMyQuestions

Answer 3

Never learned this

Answer 4

Sorry

Answer 5

D: aw okay

Answer 6

positive zeros: let x=1, and count how many times the signs change

negative zeros: let x=-1, and count how many times the signs change

complex zeroes, they eat up pairs of positive or negative zeros

Answer 7

just by the complex alone .. there are only 2 options that can work, since complex zeros have to come about in even pairs

Answer 8

so its either a or d ?

Answer 9

a or c ... yes

Answer 10

counting the positive sign changes will be helpful

Answer 11

i think its c ...

Answer 12

why do youwant to pick c?

Answer 13

Wouldnt I just use descartes rules to solve this.?

Answer 14

descartes rule of signs yes

Answer 15

let x=1

-7 - 12 + 9 - 17 + 3
| | |
0 1 2 3

i see 3 sign changes for a postive x

Answer 16

so, its possible to have 4 roots total giving us:

p,n,c
3,1,0
1,1,2