Question

What are the possible number of positive real, negative real, and complex zeros of
f(x) = 6x^3 – 3x^2 + 5x + 9?

Answer 1

count sign changes for f(x) and f(-x)

f(x) --> +-++ 2 sign changes
f(-x) --> ---+ 1 sign change

cubic function must have 3 zeroes
positive: 0 or 2
negative: 1
complex: 0 or 2