Find a counterexample to a statement Algebra I

Find a counterexample to the following statements among the different propositions.

" f\left(x\right)=x^2-3x+2 has no real positive root."

-1 is not a root of f.

2 is a root of f.

f\left(x\right)=x^2-3x+2 has two real positive roots.

f\left(x\right)=x^2-3x+2 has no real negative root.

"All odd numbers are prime."

2 is even and prime.

3 is odd and prime.

6 is even and composite.

9 is odd and composite.

"All even numbers can be written as a power of two, such as 2=2^1 and 4=2^2."

8=2^3

7 can not be written as a power of 2.

16 is even and can be written as a power of 2.

6 is even and can not be written as a power of 2.

"All prime numbers are odd."

4 is even and not prime.

3 is odd and prime.

2 is even and prime.

15 is odd and not prime.

" f\left(x\right)=x^2-3x+2 has no real positive root."

−2 is a root of f.

f has not real negative root.

f has positive roots.

6 is a root of f.

"All animals living in the ocean are fish."

Mahi mahi live in the ocean.

Whales live in the ocean and they are not fish.

Salmon are fish who do not live in the ocean.

Fish do not live in the ocean.

" f \left(x\right) = x ^ 2 -x-12 has no real negative roots."

−3 is a root of f(x).

f does not have any positive root.

4 is a root of f(x).

f has positive roots.