Which expression is a trinomial?

• A. x^2 + 3x + 2
• B. x^2 + 3x
• C. x^2
• D. 3x + 2

Answer: (A)

A trinomial is an algebraic expression that has three terms, separated by plus or minus signs. The expression x^2 + 3x + 2 has three parts: x^2, 3x, and 2, so it has three terms and is a trinomial. The other expressions each have two terms or one term: x^2 + 3x is a binomial (two terms), x^2 is a monomial (one term), and 3x + 2 is a binomial. So the expression with three terms is the one that fits being a trinomial.