Question

Can someone check this for me? Thanks!

Answer 1

Answer:

two or zero positive real roots, one or zero negative real roots

Step-by-step explanation:

f(x) = 9x³ − 2x² − x + 5

There are 2 sign changes, so the number of positive real zeros is 2 or an even number less than that.  So there are two or zero positive real roots.

f(-x) = 9(-x)³ − 2(-x)² − (-x) + 5

f(-x) = -9x³ − 2x² + x + 5

There is 1 sign change, so the number of negative real zeros is 1 or an even number less than that.  So there is exactly 1 negative real root.

Your answer is correct.