Question

What are the possible number of positive, negative, and complex zeros of f(x) = -3x4 + 5x3 - x2 + 8x + 4?

Answer 1

a Positive: 2 or 0; Negative: 2 or 0; Complex: 4 or 2 or 0

b Positive: 1; Negative: 3 or 1; Complex: 2 or 0

c Positive: 3 or 1; Negative: 1; Complex: 2 or 0

d Positive: 4 or 2 or 0; Negative: 2 or 0; Complex: 4 or 2 or 0

Answer 2

like the other one right?

Answer 3

yes

Answer 4

lets see if i can not screw up

\[f(x) -3x^4 + 5x^3 - x^2 + 8x + 4\]
3 changes in sign, 3 or 1 positive zero right?

Answer 5

right. that makes sense

Answer 6

now we are done since that leaves only one option
we could compute \(f(-x)\) too but it seems there is no need

Answer 7

okay. so letter C. thanks for the help