Which of the following is a trinomial?

Although you didn't provide any answer choices:

A trinomial is an expression with exactly three terms that can't be combined an example would be this

x^2 - 3x + 1

None of those terms can be combined

x^2 + 3 - 4 has three terms but it isn't considered a trinomial because you can simplify it to x^2 - 1 which is known as a binomial because it has 2 terms in it's simplified form.

hope this helps C: